Section I. INTRODUCTION
1. GENERAL. a. Most Japanese equipment shows evidence of careful thought to adapt it to the needs of the soldier. The Japanese Army expects to fight, mostly on foot, in all the varied climates and terrains of Asia, where roads often are lacking. The equipment therefore is made as light in weight as is practicable, and, when possible, is arranged to pack on horses or to be carried by men. The Japanese have given much attention to animal pack, and there are a great variety of pack saddles for specialized purposes. All of the organic heavy infantry weapons are designed for animal pack and can be manhandled when necessary.
b. The two-wheeled military cart is the most common vehicle. This cart, of which four types are known, is built almost entirely of wood. The smallest has a capacity of about 400 pounds. It is strong and light and is pulled by one horse which the driver leads. A larger type, of greater capacity, is pulled by two horses. A heavier military vehicle also has been developed which often is designed to carry artillery spare parts or other heavy equipment. This vehicle is pulled by either 2 or 4 horses.
c. Most of the Japanese Army's automotive equipment is of foreign design and construction. However, Japanese models have been designed and constructed. These are of two general types: a 4-wheeled commercial design of about 2 tons capacity, and a 6-wheeled military vehicle of larger size, made in several capacities but according to the same general design. Originally, these heavier vehicles were equipped with 6-cylinder, heavy-duty, gasoline engines, but later types have Diesel engines. This trend toward Diesel power no doubt will be intensified.
d. Japanese engineering equipment is fairly complete, and includes a wide variety of amphibious, construction, maintenance, and demolition equipment. Heavier equipment, however, does not appear to have been developed on a scale comparable with the American standard. The following types of Japanese equipment are described in the chapters indicated below:
Type of equipment Chapter Air corps equipment 4 Chemical equipment 9 Armored unit equipment 9 Personal equipment 11
Definite information concerning ordnance and other mobile maintenance equipment has been omitted because of lack of available data. There is sufficient evidence, however, to conclude that such equipment exists in the Japanese Army.
Section II. INFANTRY EQUIPMENT
1. GENERAL. Details of infantry equipment have not been shown in this section when it has been possible to place them under specific headings. For example, personal items issued to the individual soldier have been described, where possible, under chapter 11, while weapons are treated in chapter 9.
2. OBSERVATION EQUIPMENT. All reported specimens of Japanese optical instruments have been of good quality and have been found to resemble German designs. A particularly wide range of patterns has been developed, and specimens examined have been characterized by sturdy construction. In all cases definition in the central part of the field of view was good. There are no indications that the Japanese have attempted to tropic-proof these instruments.
a. Binoculars. Details of binoculars, having a magnification in excess of 8 X, are shown in the Artillery Equipment section of this chapter. Tabulated below are the characteristics of some Japanese binoculars, of 8 X magnification or less.
Magnification Field of view Size of objective lens ° mm 8 X 6.25 56 7 X 7.1 50 6 X 9.3 24
Figure 283. Japanese binoculars, filters, and carrying case. These binoculars have a 7 X magnification and a 7.1° field of view. Special color filters may be fitted over the eyepieces.
Figure 284. Periscope binocular, weighing 1.9 pounds, has a 10 X magnification and a 3° field of view.
Figure 285. The hand held periscope, weighing 2.3 pounds, has a 5 X magnification and 10° field of view.
3. INFANTRY FIRE CONTROL EQUIPMENT.
a. Range finders.
Figure 286. Model 92 (1932) 40-cm base range finder is calibrated for measuring<
ranges up to 1,500 meters (1,640 yards).
It is a coincidence type of range finder with a 4 X magnification.
b. Aiming and laying devices.
Figure 287. Collimator sight for model 97 (1937) infantry mortar.
Figure 288. Panoramic sight for model 94 (1934) mortar has a 3 X magnification and a 13° field of view. Micrometer drums enable readings to be made to the nearest mil.
Figure 289. Telescopic sight for model 96 (1936) 6.5-mm light machine gun.
The magnification is 2.5 X, the field of view is 13 degrees, and the weight is 20 oz.
The reticle (Graticule) pattern provides for drift and windage, and is calibrated
for a maximum range of 1,500 meters (1,640 yards).
(Above) Figure 290. Telescopic sight for model 92 (1932) 7.7-mm machine gun<,br> has a 4 X magnification, a 10° field of view, and a weight of 3 lbs., 6 ozs.
(Left) Figure 291. Telescopic sight for the model 94 (1934) 37-mm gun.
4. PERSONAL ARMOR. a. Model 99 (1939) armor shields, portable.
Figure 292. Model 99 (1939) armor shield, size 12 in.x16 in.,
with the model 96 (1936) 6.5-mm light machine gun.
(1) General. While these shields are suitable for use in the open, specimens, constructed from what appears to be face-hardened plate, have been found built into the weapon ports of pillboxes. Two sizes have been recovered, the larger measuring 14 by 20 by 1/4 inches (fig. 293) and the smaller 12 by 16 by 1/4 inches.
Figure 293. Rear of armor shield, size 14 in.x20 in., showing penetration made with .30 cal. AP ammunition at 100 yards range and 30° angle of impact from normal.
(2) Penetration. Tests have shown that these shields will resist penetration by .30 caliber ball ammunition at 100 feet. However, some damage may be caused by flaking (chipping). These shields have been penetrated readily by .30 caliber AP ammunition as indicated below:
Angle of impact
Results 33 10°-15° Clean penetration and heavy flaking. 100 30° Do. 200 Normal Clean penetration. 500 Normal No penetration.
b. Body armor.
Figure 294. Bullet-proof vest.
(1) Bullet-proof vest. The vest (fig. 294) is made from olive-green drill cloth, with 3 pockets on each side to accommodate armor plates arranged in fish-scale fashion. Characteristics are as follows:
Weight complete 9 pounds. Thickness of plates 0.08 inch. Plate overlap 0.05 inch.
It is believed that the weight of this vest would preclude its general use by infantry and probably would tend to confine its use to special troops. Tests have shown that the plates are penetrated easily by .303 ball ammunition at 100 yards range, with a 30° angle of impact from normal.
(2) Body protector. No details are available concerning this body protector (fig. 295), but it is reasonable to assume that it is made from an armor plate of thickness approximating that of the bullet-proof vest. It is possible that the armor plate is in 3 sections for purposes of flexibility.
c. Steel helmets. See chapter 11.
Figure 295. Unidentified body protector.
Section III. ARTILLERY EQUIPMENT
1. GENERAL. a. Optical instruments are outstanding among specimens of Japanese artillery equipment. Examination of them shows good, versatile design, sturdy construction, and satisfactory definition. Knowledge of antiaircraft fire-control equipment is limited; specimens examined to date are obsolescent, although it is entirely possible that much improved designs exist, but have not yet been encountered.
b. Artillery communication equipment is described in the Signal Equipment section of this chapter. Trucks and other automotive equipment are described in the Automotive and Land Transport section.
c. Although the Japanese Army is provided witha variety of prime movers, few types of these have been encountered in forward areas. These have been older models; more modern types, with improved specifications, well may exist.
2. ARTILLERY FIRE CONTROL INSTRUMENTS. a. General. Illustrated and described on the following pages are various examples of artillery fire control equipment used by the Japanese. Their optical equipment is well made, sturdy, and versatile, but none examined differs from standard optical design. Panoramic sights for artillery weapons have not been recovered, but sights for infantry guns and mortars (described in sec. II) suggest that the Japanese have suitable sights for use on artillery pieces.
b. Off-carriage fire-control instruments.
Figure 296. The 75-cm. base range finder is an inverted coincidence-type range finder with a 12 X magnification, a vertical field of view 2°, and a 3° horizontal field of view. It is calibrated to measure ranges up to 10,000 meters.
Figure 297. One meter base stereoscopic range finder. The reticle of this instrument is graduated from 250 to 6,000 (presumed to be meters). Markings indicate an 8° X magnification, a 4.5° vertical and 5° horizontal field of view.
Figure 298. The model 93 battery commander's telescope permits measurement of angle of site from --300 to +300 mils, as well as measurement of azimuth. An unusual feature is that the telescopes cannot be placed in a horizontal plane for better stereoscopic vision. It has an 8 X magnification and a 6° field of view.
Figure 299. This battery commander's telescope has an 8 X magnification and a 6° field of view. It is constructed so that the telescopic arms may be placed in a horizontal position for better stereoscopic vision.
Figure 300. Battery commander's telescope. Although giving a high magnification and wide field of view, the individual telescopes cannot be placed in a horizontal position to improve stereoscopic vision.
Figure 301. This artillery spotting telescope may be used with three different eyepieces, each of which gives a different magnification--the maximum being 33 power. Provision is made to measure azimuth, and elevation (from -30° to +30°).
c. Aiming and laying devices.
Figure 302. This panoramic sight appears to have been designed for use on more than one artillery piece. It is shown above mounted on the model 41 (1908) infantry gun. The sight has a 3 X magnification and a 13 degree field of view.
Figure 303. This aiming circle has a 4 X magnification and a 10° field of view. Similar to the American aiming circle, it is used by artillery units for measuring angles in azimuth and site, and for general topographical work.
Figure 304. This gunner's quadrant is calibrated from 0 to 90°, with a vernier reading to 1/16 of a degree.
Figure 305. This gunner's quadrant is calibrated in units of 10 mils, extending from 0 to 1,410 mils (79°). A vernier scale enables adjustment to the nearest mil. It is considered possible that this quadrant has been designed primarily for use with the model 41 (1908) 75-mm infantry gun.
3. ANTIAIRCRAFT FIRE CONTROL EQUIPMENT. a. Automatic weapons.
Figure 306. Front and rear antiaircraft sights mounted on the model 92 (1932) 7.7-mm machine gun.
The model 92 (1932) 7.7-mm and the single mounted model 93 (1933) 13-mm machine guns, described in chapter 9, are provided with antiaircraft ring sights. The latest type ring sight recovered, illustrated in figure 306, is rotated automatically around its horizontal axis as the gun is elevated. It is believed that the purpose of this design is to correct automatically for the angle of approach. The following automatic weapons are provided with more complex sights than the ring sights.
Figure 307. Computing head for AA sight used on dual mounted model 93 (1933) 13-mm machine gun.
(1) Dual-mounted model 93 (1933) 13-mm machine gun. To date only incomplete sights (fig. 307) have been examined on dual mounts. They are constructed in such a manner that estimates of target course and speed are fed into the instrument, which then applies the appropriate deflection to the sighting telescope. The sight would appear to require 3 men for its operation.
(2) Model 98 (1938) 20-mm automatic cannon. Complete antiaircraft sights for this weapon have not yet been recovered. It is known that some form of computing sight is used.
(3) Model 96 (1936) 25-mm automatic cannon. A computing sight, similar to the one described in a (2) for the 13-mm machine gun, is provided for this weapon (fig. 308) .
Figure 308. Computing sight for Japanese model 96 (1936) 25-mm automatic cannon.
(4) Vickers type 40-mm automatic cannon. This weapon also has a computing sight for use in antiaircraft fire. In addition, an automatic fuze setting mechanism is provided. The time setting given to each fuze is adjusted, thru a complex series of gears and linkages, by the manipulation of the gun in elevation and depression.
b. Heavy antiaircraft weapons. According to modern standards the Japanese heavy antiaircraft fire control equipment seen to date has been outmoded and designed for use with the Model 88 (1928) 75-mm antiaircraft gun. Off-carriage fire-control instruments and computing mechanisms used with these guns are as follows:
Figure 309. 2-meter-base height and range finder.
(1) 2-meter-base height and range finder. This instrument (fig. 309) is of good optical construction and standard, but most specimens recovered had no provision for electrical data transmission. It supplies the "present altitude" to the guns.
Figure 310. Target speed and course angle calculator with carrying box.
(2) Target-speed and course-angle calculator. This instrument (fig. 310) is mounted on a tripod for use. The illustration in figure 310 does not include an elbow telescope, which must be mounted on its top in order to operate the instrument. The calculator supplies the angle of approach (course angle) of the target at the present position and ground speed of the target.
Figure 311. Powder-charge temperature and wind correction scale.
(3) Corrector scale. This is a metal board (fig. 311) on which may be read mechanically the correction angles required for wind direction and powder temperature.
Figure 312. Model 89 (1929) 10-cm AA spotting binoculars.
(4) Spotting binoculars. These are used to obtain spot corrections, and have 15 X magnification and 4° field of view (fig. 312) .
Data from each of the instruments shown in figures 309, 310, 311, and 312, are shouted to the gun crew, certain individuals of which operate the "on carriage" components. This procedure theoretically results in the gun being correctly aimed and the time fuzes being so adjusted that the projectiles burst on the target. The "on carriage" components are:
(a) Elevation computing apparatus.
(b) Azimuth computing apparatus.
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(c) Auxiliary elevation and lead correction disc.
(d) Fuze setter.
c. Computing director. A few data computing directors have been captured, and provision for electrical data transmission has been seen on height finders. Mounting surfaces for data receivers have been found on some model 88 (1928) 75-mm anti-aircraft guns. There is evidence of more general use of electrical data transmission and computing directors than would be indicated by the equipment captured to date.
d. Searchlights. Japanese searchlights include the following sizes:
60-cm (23.6 inches).
90-cm (35.4 inches).
98-cm (38.6 inches).
100-cm (39.4 inches).
110-cm (43.3 inches).
150-cm (59.1 inches) (fig. 313).
Figure 313. 150-cm searchlight.
The following equipment is used by Japanese searchlight units:
(1) Generator truck (standard 2-ton truck chassis).
(2) Searchlight comparator. The searchlight comparator illustrated in figure 314 is an instrument with which an observer, by keeping a plane in the crosslines of the telescope, automatically directs the searchlight on the plane. It was found satisfactory for operation of U.S. searchlights.
Figure 314. Searchlight comparator.
(3) Sound locator. Several varieties of Japanese sound locators are known to exist. One of the small models is illustrated in figure 315.
Figure 315. Small sound locator.
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4. PRIME MOVERS AND TRACTORS. a. Komatsu tractor.
Figure 316. Komatsu tractor.
This small, full-tracked vehicle (fig. 316) is designed solely for towing purposes. Steering is of the clutch-brake type, with hand levers operating the clutches. Two foot brakes are located on the right side, and are so placed that either or both brakes may be operated by the right foot. The gear box allows 3 forward and 2 reverse speeds. The vehicle is supported by 4 small bogie wheels on each side. Examination of a specimen revealed that a number of the bearings were of Swedish manufacture. Characteristics are as follows:
Weight 3 tons (estimated) . Length 8 feet 2 inches. Width 4 feet 4 inches. Engine 4 cylinder, gasoline. Cooling Water. Ignition Bosch magneto. Length of track in contact with ground. 5 feet 7 inches. Width of track 10 inches.
b. Light prime mover.
Figure 317. Light prime mover.
The model number and date of manufacture of this vehicle (fig. 317) are not known.
In the case of a specimen examined, the word "seventy" was found marked in English on the side of the radiator, probably indicating the engine horsepower. A name plate on the power unit shows it to be a "Kato engine model K 3." Suspension consists of 2 bogies mounted on each side of the vehicle. Each bogie has 3 small wheels, and the sprocket is at the rear. Details are reported to be as follows:
Approximate characteristics Weight 4 tons (estimated) . Length, width, height No details. Engine 4 cylinder, gasoline. Cooling Water. Length of track in contact with ground. 7 feet 5 inches. Diam. of sprocket 2 feet 2 inches.
c. Model 92 (1932) 5-ton prime mover. It is reported that there are 2 variations of this vehicle. Model A is powered by a 6-cylinder in-line "L" head "Sumida" gasoline engine, and model B by a 6-cylinder in-line, air-cooled "Isuzu" Diesel. As far as may be ascertained, with exception of a modification in radiator design, the general appearance and suspension of these 2 models are similar. Both vehicles are reported to be identical in the following respects:
Common characteristics Length 11 feet 8 inches. Width 5 feet 11 inches. Height 7 feet 8 inches. Ground clearance 113/4 inches. Fording depth 1 foot 71/32 inches. Grade 30°. Turning radius Can pivot. Winch capacity 23/4 tons.
(1) 5-ton prime mover (model A) (fig. 318).
Figure 318. 5-ton prime mover (model A).
Note. The model A is believed to be similar to, if not identical with, a recently examined prime mover. This vehicle was found to be well constructed and capable of
Characteristics Weight 51/3 tons. Engine 6 cylinder, "Sumida." Cooling Water. Cylinder bore 110-mm (4.3 inch). Piston stroke 135-mm (5.3 inch). Horsepower 64 to 98 (160 theoretically indicated hp at 2,800 rpm--
based on reported engine specifications).
Ignition Bosch magneto. Generator Bosch 12 volts. Storage batteries 2-12 volts, 60 amperes. Fuel tank capacity Main 27.5 gallons, auxiliary 12.1 gallons.
operating over most types of terrain. The present gasoline engine is estimated to be of approximately 140 horsepower, considerably more powerful that the standard unit. It is believed that this particular engine is a replacement of the unit originally installed.
(2) 5-ton prime mover (model B) (fig. 319).
Figure 319. 5-ton prime mover (model B).
Characteristics Weight 5.5 tons. Engine 6 cylinder, Diesel. Cooling Air. Cylinder bore 110-mm (4.3 inch). Piston stroke 140-mm (5.5 inch). Horsepower 65 to 90 (135 theoretically indicated hp at 2,000 rpm--
based on reported engine specifications).
Ignition Compression. Generator 12 volts, 300 watts. Storage batteries 2-12 volts, 120 amperes. Fuel tank capacity Main 22 gallons, auxiliary 13.2 gallons.
d. Model 92 (1932) 8-ton prime mover. It is reported that 2 versions exist of this vehicle; the model A is powered by a 6-cylinder in-line, water-cooled gasoline engine, and the model B by a 6-cylinder in-line water-cooled Diesel. The following data are believed to be common to both models A and B:
Common characteristics Length 14 feet 1 inch. Width 6 feet 6 inches. Height 8 feet 6 inches. Grade 15°. Winch capacity 5 tons. Cylinder bore 130-mm (5.1 inches). Characteristics of model A Weight 8.4 tons. Ground clearance 11 1/2 inches Engine 6-cylinder, gasoline. Cooling Water. Piston stroke 5.6 inches. Horsepower 80 to 130 (230 theoretically indicated hp at 2,800 rpm--
based on reported engine specifications).
Ignition Bosch magneto. Generator 12 volts, 100 watts. Storage batteries 2-12 volts, 100 amperes. Fuel tank capacity Main 39 1/2 gallons, auxiliary 9 gallons.
Characteristics of model B Weight 9.3 tons. Ground clearance 12 inches. Engine 6 cylinder, Diesel. Cooling Water. Piston stroke 6.4 inches. Horsepower 105 to 120 (215 theoretically indicated hp at 2,000 rpm--
based on reported engine specifications).
Generator 12 volts, 500 watts. Storage batteries 4-12 volts, 140 amperes. Fuel tank capacity Main 391/2 gallons, auxiliary 9 gallons.
e. Model 98 (1938) 4-ton prime mover.
It is believed that this prime mover, powered by an 8-cylinder V-type air-cooled gasoline engine, is capable of hauling a load at 25 miles per hour, and that it can travel a distance of 125 miles in a period of 10 hours. Steering is of the clutch brake type, with foot and hand operated brakes. A central selector type gear box allows 4 forward speeds and 1 reverse.
Although no 4-ton model has been encountered as yet, it is believed that the following data apply:
Characteristics Weight 4 tons. Length 12 feet 5 inches. Width 6 feet 1 inch. Height 7 feet 3 inches. Ground clearance 11 1/2 inches. Tread No details. Fording depth 20 inches. Grade 30°. Turning radius Can pivot. Winch capacity Over 2 tons. Engine 8 cylinder V-type, gasoline. Cooling Sirocco type fan. Cylinder bore 90-mm (3.5 inch). Piston stroke 125-mm (4.9 inch). Horsepower 73 to 88 (130 theoretically indicated hp at 2,800 rpm--
based on reported engine specifications).
Ignition Bosch magneto. Generator Bosch, 75 watts. Storage batteries 12 volts, 80 amperes. Fuel tank capacity Main 22 gallons, auxiliary 13 gallons.
f. Model 98 (1938) 6-ton prime mover.
Figure 320. Model 98 (1938) 6 ton prime mover.
Examination of this prime mover (fig. 320) indicates that it is an unarmed artillery tractor, suitable for the additional roles of reconnaissance vehicle and ammunition carrier. Suspension follows the pattern of the model 2597 medium tank. Since steering is of the clutch-brake type, the vehicle is capable of turning within its own length. It is reported that this vehicle is used as a prime mover for the 105- and 150-mm howitzers and the 105-mm gun. Details are believed to be as follows:
Weight 7.75 tons. Length 14 feet 1 inch. Width 6 feet 9 inches. Height 6 feet 3 inches. Ground clearance 131/2 inches. Grade 15° pulling field gun. Turning radius 19 feet. Winch capacity 5.5 tons. Engine 6 cylinder, Diesel. Cooling Water. Cylinder bore 120-mm (4.7 inch). Piston stroke 155-mm (6.1 inch). Horsepower 88 to 110 (175 theoretically indicated hp at 2,000 rpm--
based on reported engine specifications).
Generator 24 volts, 100 watts. Storage batteries 2-12 volts, 180 amperes. Fuel tank capacity Main 17.6 gallons, 1st auxiliary 18.7 gallons, 2d auxiliary 6.6 gallons.
g. Model 95 (1935) 13-ton prime mover. This heavy prime mover is reported to be produced in two models: the model A is powered with a 6-cylinder in-line, water-cooled, gasoline engine; the model B with a 6-cylinder, water-cooled Diesel. Both models are believed to be equipped with multiple disc, clutch type steering, with hand and foot operated brakes. The following data is reported to be common to both types:
Length 16 feet. Width 7 feet 6 inches. Height 9 feet 3 inches. Ground clearance 12 inches. Grade 13 tons, 15°--29 tons, 71/2°. Turning radius 65 feet. Winch capacity 111/4 tons. Characteristics of Model A Weight 14.3 tons. Engine 6 cylinder, gasoline. Cooling Water. Cylinder bore 5.4 inches. Piston stroke 6 inches. Horsepower 130 to 160 (265 theoretically indicated hp at 2,800 rpm--
based on reported engine specifications).
Ignition Magneto. Storage batteries 2-120 volts, 80 amperes. Fuel tank capacity Main 61.6 gallons, auxiliary 91/2 gallons. Characteristics of Model B Weight 15 tons. Engine 6 cylinder, Diesel. Cooling Water. Cylinder bore 5.6 inches. Piston stroke 7.6 inches.
Characteristics of Model B--Continued Horsepower 145 to 165 (295 theoretically indicated hp at 2,000 rpm--
based on reported engine specifications).
Generator 300 watts. Storage batteries 2-12 volts, 80 amperes. Fuel tank capacity 60 gallons.
5. CAISSONS, LIMBERS, AND OTHER ARTILLERY VEHICLES. a. Caissons and limbers.
Figure 321. Typical horse-drawn caisson and limber.
(1) Horse-drawn caisson and limber. Figure 321 depicts a typical Japanese horse-drawn caisson and limber, for use with the 75-mm field gun. Mounted on standard artillery, iron shod, wooden wheels, the two units are drawn by six horses. Characteristics are reported as follows:
Total weight (empty) 2,130 pounds (approximately). Weight (loaded): Limber only 1,750 pounds. Caisson only 2,080 pounds. Capacity: Limber 40 rounds. Caisson 60 rounds. Diameter of wheels 55 inches.
Caissons and limbers of design similar to figure 321, but carrying fewer rounds, are provided for field guns of heavier caliber.
Figure 322. Alternative type caisson and limber for 105-mm field gun.
(2) Alternative type caisson and limber. The caisson and limber illustrated in figure 322 is an alternative type for use with the 105-mm field gun. Primarily designed to be towed by a tractor, it also may be drawn by six horses. The heavy artillery-type wheels have solid rubber tires. Characteristics are reported as follows:
Total weight (empty) 2,530 pounds. Total weight (loaded) 5,040 pounds. Total capacity 48 rounds. Diameter of wheels 55 inches.
Figure 323. High speed caisson for 75-mm ammunition.
(3) High-speed caisson. The photographs illustrated in figure 323 show the most modern type of
Japanese caisson seen to date. Constructed of metal, it is mounted on steel disc wheels, of comparatively small diameter, fitted with solid rubber tires. The probable capacity of the caisson is 48 complete rounds of 75-mm ammunition. Units of similar appearance carry a smaller quantity of 105-mm ammunition.
b. Battery wagons.
Figure 324. Battery wagon for model 88 (1928) 75-mm antiaircraft gun.
(1) Battery wagon for antiaircraft gun. The trailer (fig. 324) apparently is constructed for high-speed transportation of communication equipment, miscellaneous spare parts, and bulk ammunition. The body is made from lightweight metal plate, which is not considered to be proof against small-arms fire. Compartments are provided for the stowage of the various items of equipment carried. This vehicle is mounted on metal disc wheels fitted with pneumatic tires. For antiaircraft defense, a tripod, apparently designed for the model 92 (1932) 7.7-mm heavy machine gun, is mounted on the roof. Characteristics of the vehicle are as follows:
Over-all length of frame 11 feet 10 inches. Width 6 feet 3 inches. Wheel base 7 feet 7 inches. Ground clearance 12 inches.
Figure 325. Battery wagons for use with field artillery.
(2) Battery wagons for field artillery. These units are similar to the horse-drawn limber and caisson in construction (fig. 325). They are used for the transportation of general artillery equipment, such as range finder, binoculars, battery commander's telescopes, communication materials, tools, etc. Characteristics are reported to be as follows:
Total weight loaded (limber and caisson). 4,318 pounds. Diameter of wheels 55 inches.
c. Spare parts wagons.
Figure 326. Spare parts wagon for 150-mm howitzer.
These are used for the transportation of spare parts, tools, and maintenance and repair materials (fig. 326). Characteristics are believed to be as follows:
Total weight loaded (limber and wagon). 3,770 pounds. Diameter of wheels 55 inches.
The two units are normally drawn by 6 horses.
6. PACK EQUIPMENT. a. General. Great attention has been paid to the development of pack transportation of infantry support guns, namely, models 41 (1908) and 94 (1934) 75-mm mountain pack guns (sec. II, chap. 9), as well as of machine guns, ammunition, supplies, etc. Illustrations
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on the following pages show in detail pack saddles, draught harness, and an infantry support gun, broken down into loads averaging 200 pounds per load and packed for horse transportation.
b. Pack saddles.
Figure 327. Standard pack saddles.
Two standard pack saddles are illustrated in figure 327. The saddle is adjustable so that it comfortably fits the back and girth of the horse. Saddle A carries the weapon (such as a heavy machine gun); Saddle B is fitted to hold ammunition or spare-parts chests. (See also figs. 323-334.)
c. Draught horses.
(Below) Figure 336. 4 draught horse harness with saddles.
Extensive use of draught horses is made by the Japanese. Figure 336 shows a typical 4-horse harness hookup, with the type of saddle (which differs from the cavalry saddle) used by artillery and infantry gun crews.
Figure 328. Tube of model 41 (1908) 75-mm infantry (mountain) gun fastened to pack saddle.
Figure 329. Trail of 75-mm infantry (mountain) gun disassembled and fastened to pack saddle.
Figure 330. 75-mm infantry (mountain) gun cradle on pack saddle.
Figure 331. Shield for 75-mm infantry (mountain) gun folded and fastened to pack saddle (with tool chest attached to side).
Figure 332. Breech mechanism and tray for 75-mm infantry (mountain) gun.
Figure 333. Wheels and axle attached to pack saddle.
Figure 334. Method of fastening ammunition chest to pack saddle.
Figure 335. Standard ammunition chest for 75-mm infantry (mountain) gun.
The chest, made of steel plate, carries 6 rounds. It weighs 29 pounds empty and 118 pounds with ammunition.
Two chests can be carried on one pack saddle.
Section IV. SIGNAL EQUIPMENT
1. GENERAL. The following data have been derived from the examination of Japanese signal equipment.
2. RADIO EQUIPMENT. a. Ground. (1) The Japanese place most emphasis on wire communication. However, radio is used initially where communications must be established rapidly or where other means are not practicable. After wire communications have been established, radio assumes a secondary role as a stand-by communication link except where other means cannot be employed.
(2) Apparatus, to date, is of obsolescent design. Circuits and components are comparable with those used by the Allied Nations between 1935 and 1937. Transmitters and receivers almost invariably have wide frequency ranges and use plug-in coils to cover the various bands. In regiments or smaller units, transmitters generally vary from approximately 1 to 50 watts. High-powered sets (500 watts and above) are used primarily for Army administrative traffic and air/ground liaison. Simple Hartley oscillator circuits, connected directly to the antenna, are used. The smaller receivers employ regenerative detectors without radio frequency amplification. While such arrangements are simple to service and maintain, the frequency stability suffers greatly. It therefore would be difficult to "net" these radio sets and keep them on frequency.
(3) A great variety of small transceivers and transmitter-receiver combinations of 1 to 2 watts power are in operation. Such sets are usually man-pack. The transceivers are contained in one case which is carried on the chest; the batteries are carried in another case on the back. In the small transmitter-receiver models, the transmitter, receiver, batteries, and the hand generator for transmitter power, are all carried in separate cases, making it necessary for two to three men to pack and operate a set. Sets of from 10 to 50 watts power are usually of the portable type, and are carried in 4 or 5 separate cases. Power connections are made by means of plugs and cables. The sets, in general, have a complexity of control which does not permit ease of operation. The many controls of the Direction Finder and Intercept Receiver, Model 94 (1934), Type 1, indicate that a comparatively long time is necessary to obtain an accurate "fix" on a transmitter. It must be borne in mind, however, that Japanese operators are well trained and capable of making good use of their equipment.
(4) Most of the transmitters have provision for crystal operation, and, although few crystals have been found, it is reasonable to assume that crystal operation is used extensively. All crystal operated Army ground sets also can be employed as master oscillators.
(5) Since many ammeters, both for antenna and power, are supplied with separate shunts, the same meter movement can be used for many different sets.
(6) Examination of equipment shows that there is little indication of moisture- or fungus-proofing.
(7) All phone transmitters are amplitude modulated, and there is no evidence of frequency modulation.
(8) Technical characteristics and photographs of sets used by Japanese ground forces are illustrated in figures 337 to 354.
Figure 337. Model TE-MU Type 2. Transmitter. Front view.
Figure 338. Model TE-MU Type 2. Transmitter. Rear view.
Tube shown is Japanese Type UV812, Mfgd. by Tokyo Electric Co.
Figure 339. Model 94 Type 1. Transmitter. Front view.
140-15000 KC. MOPA. 275 watts.
Figure 340. Model 94 Type 1. Transmitter. Rear view.
140-15000 KC. MOPA. 275 watts. Tube at left of photo is Japanese Type UY511-B master oscillator.
Two screen grid tubes in center are parallel connected PA Tubes, Japanese Type UV812.
Figure 341. Model 94 Type 2B. Transmitter-receiver. No. 55-D Transmitter.
950-6675 KC. 200 watts. Shown with power supply.
Gas driven motor generator delivers 1300 volts DC.
Figure 342. Model 94 Type 2B. Transmitter-receiver. No. 27 receiver.
140-15000 KC. 7 plug-in coils. Power supply--batteries.
Figure 343. Model 94 Type 5. Transmitter-receiver Model 32. Transmitter.
Operates CW or phone. Used with receiver shown below.
Figure 344. Model 94 Type 5. Transmitter-receiver Model 32.
Receiver. Used with transmitter shown above.
Figure 345. Model 94 3A No. 36. Transmitter-receiver.
Transmitter, 400-5700 KC. 15 watts. CW only. Power supply-hand generator.
Receiver; 350-600 KC. Power supply--batteries.
Figure 346. Model 94 Type 6. Transceiver. No. 23 Model H. Date: April 1940.
Figure 347. "Walkie Talkie" Type 66. Transceiver. Model A. 2500-4500 KC. Power supply--batteries.
Figure 348. Model 97 Type 3. Transceiver, with hand generator.
Pack type. Dipole elements of antenna fasten to wing nuts at ends of case.
Figure 349. Model TM Type 2. Transceiver, 4000-12000 KC.
CW only. Power output about 1 watt. (Also reported as 2.5 watts.)
Figure 350. Model 92 Revision 3. 7 Tube, combination TRF and superheterodyne, all-wave receiver.
200-2000 KC. Shown with AC power supply. Delivers 75 and 200 volts DC.
Figure 351. Model 94 Type 1. Direction finding and intercept receiver.
100-2000 KC. Loop shown dismounted from frame.
Figure 352. Model 94 Type 3-A. Receiver only. Pack type.
b. Airborne. (1) Japanese airborne transmitters and receivers, sturdily and compactly constructed, are of excellent workmanship and material. More attention appears to have been given to compactness of design than to ease of maintenance. In many instances, the equipment is so constructed that it is difficult, or even impossible, to service. To some extent, sets are designed to fit a particular type of aircraft, rather than standardized for general use. It has been noted that some tubes (valves) are equipped with leather handles to facilitate removal. Japanese equipment uses a large amount of aluminum, so that even bulky pieces are unusually light in weight. Although no precautions have been taken against corrosion and fungus control, reports indicate that equipment later than 1940 is far superior to that of earlier design. Electrically and mechanically, new radio equipment appears to approach Allied standards.
(2) It has been noted that not all Japanese planes have radio equipment. While radio direction finders are standard equipment on medium and heavy bombers, there have been no reports indicating that they are normally fitted to fighters.
(3) Radio equipment that was made in America, either in whole or in part, has been found on several Japanese (0) Zero fighters (Zekes). Most parts are of Japanese manufacture, but components of German and English manufacture have been noted. Exact imitations of American and German designs also have been reported. There is no evidence of quantity production; indeed, all equipment noted is hand-made and of good construction. Good quality crystals are used in the majority of radios to control the frequencies of transmitters and receivers.
(4) Technical characteristics and photographs of airborne equipment are shown in figures 355 to 363.
|Classification||Transmitter output (watts)||Form||Model||Type No.||Date of original model||Function||Type transmission||Range (miles)||RF coverage in MC||Frequency shifting capabilities||Present frequency||Antenna system||Tuning--MO or crystal (number of crystals)||Selectivity receiver||Sensitivity receiver||Receiving circuit||Transmitter circuit||Frequency stability||Meters used||Power source||Remarks|
|Transmitters||100||Portable||TE-MU||3||Used on some islands in local radio net.||Unknown CW, phone, or both.||15-20||1.5-15.0 (plug-in-coils)||Unknown (At least 1).||Wire||MO or crystal. (Number of crystals unknown.)||MOPA. Tubes used-UV202A, UX814, and UV812.||Good||220 volts. 3 phase, 50-60 cycle AC. Half wave rect. Uses 3 X968 tubes.||Medium power. Short wave portable station. Used primarily in local radio nets on island.|
|50 or 250||Fixed station||TE-MU||1942||Ground to air||CW, phone||50||3.38-10.4; 12.2-14.0 (4 bands, tapped coils and switches.)||Good. Continuous coverage.||Wire-link coupling from PA to ant. coupler. Coupling adjusted from transmitter panel.||MO||3 stages-Osc, Buffer, PA. No freq. multiplication. Keyed in buffer and PA.||Fair||Osc. indicator. Osc. plate current. Buffer plate current. PA plate current. Ant. ammeter.||Rectified AC; low power 1,000 v; high power-2,000 v.||Used with rectifier unit. Carried in 2 cases, slung on poles. Fixed station operation. Buffer and PA tubes, screen grid type. No neutralization used. Capable of low or high power operation by switching arrangement.|
|275||Semiportable. Fixed station.||94||1||1934||Hq-Army Div||CW, MCW, phone.||0.14-15.0 shift bands by plug-in coils. No. of bands and coils unknown.||Good||Unknown||Wire-2 ant. ckts. in transmitter--Series resonant for high freq., Parallel resonant for low freq.||Crystal. (Number of crystals unknown.)||MOPA-Hartley Osc. MO-UY511B. PA-two UV812 in parallel screen grid voltage keyed for CW. Grid modulation for MCW and phone.||do||Ant. ammeter. PA-plate current. PA-grid current. Osc. plate current. Fil. voltmeter.||Motor generator: 2,000 volts DC; 1,000 volts DC; 400 volts DO; 100 volts DC; 12 volts DC.||Semiportable. Fixed station operation. Weight with Mot. gen. approx. 500 pounds. 2 cases and Mot. Gen. Each case carried by 2 men. Has neon osc. indicator. Various voltages go through power distribution panel.|
|300||Semi-fixed station||Not known||Not known.||Marine ground unit.||CW only||3.0 -10.0.||Wire||Grid modulated tubes-UV202, UV865, UV-814, UV860, UV861.||Good||220 volts, 3 phase 50-60 cycle AC, output voltages 3,000 volts--2,000 volts-500 volts--300 volts. Fil. 16V rect. tubes used 9-H 830, 6-X968.||Transmitter modification No. 1: High-power, short wave fixed station. Used island to island over long distances. Has emergency power supply gas-driven generator. All filaments on DC. Tubes replicas of American types. Uses speech amplifier and modulator--4 tubes in all; 1-58, 1-56, 2-2A3. Legend on name plate for mod. unit "Modulator for type 95 Short Wave No. 4 transmitter modification No. 1".|
|500||Fixed station||95||4||1935, modified 1941.||High power, island to island.||Phone||Long distance||3.7-18.2||Wire-Uses loading coils in antenna system.||MOPA. Final tube SN 146.||do||220 volts, 2 phase, 50-60 cycle AC output voltages 2100 volts-1000 volts and 16 volts. 6 Rect tubes. Type H-836.||Transmitter modification No. 1: high power, long wave, long distance. Fixed stations. Used island to island. All filaments on DC. Final tube Japanese type; all others replicas of American tubes.|
|1,000||do||92||3||1932, modified 1941.||do||CW||do||0.05-0.6||Unknown (at least 1).||Wire||MO or crystal (number of crystals unknown).||MOPA. Tubes used-202, 865, 814, 812. Final-SN146.||do||220 volts, 3 phase, 50-60 cycle AC. Output voltages 3,000 volts-2,000 volts-500 volts-300 volts and 16 volts. Uses 9-H830 and 6-X968 rect. tubes.||High power, short wave, fixed station. Used over long distances. Not known if used on phone or CW or both.|
|1,000||do||95||Not known||1935||do||Unknown if CW, phone, or both.||do||3.7-8.0 (plug-in coils)|
|1,000||do||94||1||1934||Army Div Hq||CW phone||150||0.02-0.5||Transmitter.|
|1-2||Man pack||94||5||1934||Limited range. Comm. between Inf. units.||CW phone||5-CW, 1-2-phone||Transmitter: 0.779-3.061 (3 bands) tapped coil and switch. Receiver: 0.779-7.0 (4 bands) tapped coil and switch.||Continuous coverage on MO.||10||Wire--Same ant. for both Xmtr. and Rec. connected by Send-receive switch. Counterpoise wires incl.||MO or XTAL (number of XT ALS-10).||Fair||Poor||1 Stage RF. Regen. Det. 1 Stage AF.||XTAL or MO control (Hartley ckt.) Osc. connected to antenna.||XTAL - Fair MO-Poor.||Ant. current 0-200 Ma.||Transmitter: Hand generator in separate case. Fil.-6 volts. Plate--150 volts. (Model F) receiver: batteries. In case with receiver. Fil.--1.65 volts. Plate-90 volts.||Stationary use. One twin triode tube. Triodes in parallel for CW operation. For phone, one triode becomes mod. Two man pack and operation. Throat mike used. Model 32 transmitter; Model 32 receiver.|
|4.5-CW. 3 phone.||Portable||Not known||Not known||Portable field set||do||0.9-5.3 (3 bands)||1||Crystal||4 Tube TRF Regn. Det.||Transmitter-receiver.|
|10||Pack||94||do||1934||Field equipment in div.||CW only||0.4-6.0 (5 bands) plug-in coils. Both Xmtr. and receiver.||Continuous coverage on band used.||Unknown (at least 1).||Wire||MO or Crystal (number of crystals unknown.||Hartley Oscillator||Ant. Ammeter, Plate current.||Hand generator: 7 volts filament, 500 volts plate.||Pack transmitter-receiver.|
|15||3-Man pack||94||SP-3A-36||1934||Comm. in Inf. Cav. and F. A. from brigade down to Inf.||do||Approximate 25||XMTR. 0.4-5.7 Rec--0.35-6.0 (5 plug-in coils).||Continuous coverage for band used on MO.||1||do||Crystal or MO (number of XTALS, 1).||Fair||Very sensitive||5 Tube Superhet. Regen. 2d Det.||1 Tube Hartley oscillator.||Poor||Plate voltmeter. Ant. ammeter.||Transmitter, hand generator receiver; batteries.||Pack animal or 3 man pack. Carried in 2 wooden cases. Transmitter keyed in high volt. Neg. ckt. Transmitter-receiver type.|
|20||87||1927||Field, ground, and air.||Field-25 G/A190||0.33-0.60.|
|80-CW. 200 phone.||2-Man pack||94||2-B||1934||Commd. set in Inf. div.||do||Rec: 0.14-15.0 (7 plug-in coils) XMTR: 0.95-6.675.||Continuous coverage on band used.||Adjustable presets on dials.||Wire "L" type. Total length 29.7 yds. Counterpoise wires 22' long.||Crystal or MO (Number of XTALS 1).||5 Tube Superhet||1 Tube Hartley oscillator.||Fair||Rec--Batteries; Xmtr. -- Gasoline; driven motor generator; 12V-Fil. 1,300V-plate.||Receiver can be used for intercept. Transport by 2 man pack or car; No. 55 D transmitter; No. 27 receiver.|
|2-3 man pack||94||3-A-36D||1934||Receives CW, MCW, phone.||0.4-5.75 (5 plug-in coils)||Continuous coverage for band used.||Wire-rubber covered lead in 6 feet long. Gnd. wire same length.||do||Good||4 tubes, 1 stage RF., Regen Det. 2 stages AF.||do||Batteries: 1.5V-Filament; 22.5V-Plate; 1.5V-Bias.||Receiver only. Dials marked with luminous paint and have clamps for locking. Straps provided for carrying on back. Not a "Walkie-Talkie."|
|99||3||1939||CW, MCW, phone||Rec. 1.5-6.7 (3 plug-in trays of coils).||do||3||MO-Crystal (Number of Crystals 3).||do||2 Beam Type Tubes. Osc.-Plate Mod.||do|
|Transeivers.||0.5||Man pack||94||6||1934||Walkie-talkie type. In Inf.||CW, MCW, phone||1-2||24.2-49, 3 (3 bands)||Rod, 5 feet||MO||Super-regen. Det and one stage AF.||Oscillator and Mod||Antenna Ammeter||Batteries-separate case. Fil. 6V; plate 135V.||Transceiver. One coil with 3 taps and switch, 2 to 3 men to pack and operate. No. 23 Model H.|
|1||2-3 man pack||TM||2||Revis. 1942||CW only||1-2||4.0-12.0||Continuously variable.||Wire with reel--to vary length, and tune ant. ckt.||do||Poor-except when on verge of Osc.||Extremely poor||Regen. Det. one stage AF.||2 tubes in parallel. Hartley osc.||Poor-Freq. shift when keyed.||Fil. voltmeter Ant. ammeter.||Rectified AC. DC voltages-- 150 and 180 V.||Transceiver. Portable 2 or 3 man pack, cycle, or car. Revision 2. Transmitter output also reported as 2 1/2 Watts, and R. F. coverage as 4.5-11 M. C.|
|1-2||Walkie-talkie||97||3||1937||Walkie-talkie, also air Gnd.||CW, phone||2-3||25.5-31 (tapped coil and switch).||Continuous coverage.||Dipole-- each half 23 inches long. Elements fasten to case.||do||Poor||Poor||Super-regen. Det. and One stage AF.||Master Osc, (Hartley) and modulator.||Poor||Antenna ammeter||Hand generator: Fil.--3 volts, Plate--135 volts.||Transceiver--Uses one twin triode, UX 19, for all functions. Dipole elements of ant. fasten to each end of case. Case intended to be strapped to back; Generator to chest.|
|do||Not known||66||Infantry squads, platoons.||do||1||2.5-4.5||Continuous coverage on MO||1||Either long or short antenna. Ant. tune system.||Crystal or MO. (No. of XTALS-1).||3 Tube. Regen. Det||3 tube Hartley oscillator.||do||Plate current Ant. ammeter.||Batteries: 1.5V filament; 135V plate||One man pack. Transmitter carried on chest, and batteries on back, by means of straps. Model A.|
|2||do||Not known||CW only||0.1-2.0; 4.0-5.0||5 crystals||1||Rod 6 feet long||Crystal||Transceiver.|
|2.5||Portable||do||do||Infantry ground; portable.||Several||4.5-11.0||Wire||Do.|
|Receivers||Fixed sta||92||do||1932||Comm. bet. Corps and Div.||0.2-20.0 (Use total of 7 plug-in coils at one time.)||Continuously var. for coils used.||None||do||Fair||Fair||7 Tube comb. TRF and Superhet. NoAVC.||Rectified AO||Used in conjunction with transmitter Model 94 Type 2B. Fixed station Receiver. Total of 25 plug-in coils used.|
|Direction finder and intercept receiver.||94||1||1934||Direction finder and intercept receiver.||0.1-2.0 (In 5 bands) switches and taps on coils.||Continuously variable for range of coils used.||None||Square loop--ea. side, 4-foot long. 6 turns, unshielded rotation--400° to stops.||Very selective.||Poor||6 tube TRF., 3 stages RF., Regen. Det., 2 stages AF.||Freq. calibration not good.||No visual bearing indicator used.||Batteries--1.5 V filament; 4.5V bias; 135V Plate.||Receiver only. 4 wooden chests. Weighs 350 pounds complete. Numerous controls. Slow and difficult to get a "fix." Set installed under shelter over which loop is mounted.|
Figures 353-354. Japanese radio equipment--ground.
Figure 355. Model 96 (1936) Type 3. Transmitter-receiver.
From Type 1 medium bomber (Betty). Top of unit: receiver. Bottom of unit: transmitter.
Figure 356. Radio Homing and D/F loop antenna used with some types of Japanese airborne equipment.
Figure 357. Dynamotor power supply for transmitter of model 96 Type 3 airborne radio set.
Used in Type 1 medium bomber (Betty).
Figure 358. Vibrator power supply for receiver of model 96 Type 3 airborne radio set.
Used in Type 1 medium bomber (Betty).
Figure 359. Model 99 (1939) Type 3. Transmitter-receiver.
Used in single-seater fighter (Oscar). Transmitter: 2500-5000 KC.
Receiver: 1500-6700 KC. Transmitter and receiver crystal controlled.
Photo shows complete complements of equipment.
JAPANESE RADIO EQUIPMENT--AIRBORNE
Figures 362-363. Japanese radio equipment--airborne
Classification Transmitter output (watts) Model Type No. Date of original model Function Type trans. Range miles RF coverage in MO Frequency shifting capabilities Present frequency Antenna system Tuning MO or crystal (Number of crystals) Selectivity of receiver Sensitivity of receiver Receiving circuit Transmitter circuit Frequency stability Meters used Power source Remarks Transmitter-
10 98 4 1938 V.H.F. 44.0-50.4 Unknown XTAL (number of XTALS unknown). 7 tube superhet. IF-1500KO. 3 tube Very good construction. 10 96 1 1936 Used in plane type (Zeke). CW, phone 30 Exact coverage unknown. One preset freq. cannot be changed in flight. 1 Mast behind pilot's cockpit. (See remarks). Crystal (number of crystals--1). Operates on 1 preset frequency XTAL controlled. Operates on 1 preset frequency XTAL controlled Two motor generator. For Xmtr and receiver. Use 12-volt plane batteries for power. Provides 2 way communication from plane--Same Antenna used on transmission and reception; connections made by "Send-receive" switch. Side-tone provided--Components cramped and inaccessible for servicing. 10-CW, 8.6-phone. 96 1 1936 Communicate between naval fighters. do 3.8-5.8 Preset--Not changeable in flight. Number unknown. 30-foot mast Crystal (number of crystals unknown). 5 tube superhet. IF-500KC. Appeared on planes early in 1942. 10 97 Not known 1937 Bomber, RON do 5.0-7.0 5 tube superhet 4 tubes Transmitter and Receiver on 1 frame. Reported that phone output can be scrambled. 10-CW, 6-phone. 99 6 1939 Used in (Oscar) CW, MOW, phone. XMTR--unknown, Rec.--1.5-6.7 (3 bands) Plug-in tray of coils. One preset freq. cannot be changed in flight. 1--Both XMTR and receiver. Wire--Variometer used to tune Ant. to Sets frequency. XMTR--crystal receiver--crystal controlled. (1 crystal for each). Fair Fair 5 tube superhet. RF, converter, IF, Det. and AF. HF osc. XTAL controlled. Tubes used--1-US-657A 4--KC804A. Hartley osc. Osc-807, plate mod. by 807. No speech Amp. Poor Set can be remotely controlled on CW, MOW, or phone. Receiver tuned manually. 1 set captured used ceramic insulation thru-out. Another used bakelite and is believed to be of later manufacture. Easier to machine. 10-CW, 6-phone. 99 3 1939 Used in single seat fighter. Type 01 MK II (Oscar). do CW-200, phone 100. XMTR: 2.5-5.0 Fixed coils--Receiver 1.5-6.7 (Two sets of plug-in coils). Has Ant. tuning unit so set may operate on any length Ant. Probably mast used. Could use trail wire also. Crystal (number of crystals--2). Good 4 tube superhet. 6F7A triodepent. RF, Converter, IF, Det. and AF. Local Osc. either MO or XTAL controlled. Hartley osc., UY-807A, choke Mod. by a UY807A. Xmtr--Poor. Receiver fair. Motor generator Hi voltage--600V. Tube Filaments supplied from separate 8V winding on motor generator. Main components of complete set are transmitter, receiver, power unit, control unit, and antenna tuning unit. Antenna disconnected from receiver by keying relay. Can "Listen through" while sending. 12 Not known 4 Used in Jap type 88 2EB (Lily)-- Air to air and Air to gnd. VHF. Phone only Purposely limited. Used for Short range work only. Xmtr and receiver. 44.0-50.0. Instantaneous shift to any of many preset frequencies. Instantaneous shift to any of many preset frequencies. Many preset frequencies. Variable--vertical on some planes, horizontal on others. Crystal (number of crystals Xmtr--3 Rec--3). Fair XTAL control --4 tube superhet. Uses 6F7. HF Osc. Frequency is fixed by XTAL, and IF is variable by tuning cond. XTAL control only. 3 tubes used, type 807. Good Volt- milliammeter which can be switched into various circuits for metering. Dynamotor: Supplies Hi and Lo voltage for xmtr and receiver--HiV-500V LoV-13V. Manufactured in December 1942. Entire set shows great improvement over older equipment. Simple to operate and maintain. Design especially of Receiver very modern. High grade bakelite and ceramic insulating material used throughout. On receiver, a chart shows dial setting of variable IF and proper XTAL to use to receive on certain frequency. Termed "Flying Mark 4". 20 99 4 1939 Bomber command CW only 0.45-16.5 Number unknown. Crystal (number of crystals unknown). 5 tube double superhet. 2--IF Frequency. 20 NA 3 CW, MOW Xmtr--5.0-6.93, Rec. 0.3-2.5, 1.5-15.0. do Fixed inverted "L". 22.9 ft. long. do 4 tube Dynamotor. Supplies Hi voltage for Xmtr and receiver--700v. Low voltage from planes battery--24 V. Positive lead to PA stage keyed for CW. PA grid modulated for MCW. Plane engine has ignition shielding. 20 Not known 3 Fighter command CW, phone 20 2.0-6.0 Preset--Not changeable in flight. 1 Crystal controlled superhet. 20 96 3 1936 Air to air, and to ground. In (Betty) medium Bomber. CW, MOW, phone. 200 miles from 10,000 feet on CW. 0.22-0.5, 5.0-10.0 Fixed red and trailing wire. Crystal (number of crystals--2). 6 tube Dynamotor Not D/F type. Used in med. bomber. (Betty). 25 98 4 1938 Air to ground on medium bombers. do 5-60 29.5-52.5 Preset--Not changeable in flight. Unknown MO or XTAL (number of crystals unknown). 6 tube superhet. IF-2400 KO. MOPA Transmitter and Receiver mounted separately. 25-30 96 HI No. 2 1936 Air to air and air to ground. do Xmtr--1.5-7.5 (3 bands). Rec. 1.48-7.3 (6 bands). Receiver uses plug-in coil assemblies. Preset Freq. by plug-in XTALS. Ant. lead coils for vertical "T" and inverted "L" Ant Coils-- 1.5-7.5 MO. Trail wire Ant. may also be used. MO or XTAL (MO operation by removing XTALS) (number of XTALS unknown). Good Good 5 tube superhet. RF-77,Mixer-6A7, IF-78, Det. and BFO-6F7, AF Output 41. IF Freq--400KO. 4 tube MOPA. Osc. UZ47GRF Amp-UY510B AF Amp.-UY78 Mod.--UZ-47D Supressor Grid mod. Good Dynamotor. Provision also made for use of generator. Sidetone provided for monitoring on CW--800 cycle modulation on MCW. No remote control. 26-CW 9-phone. 96 1 1936 Air to air and air to ground in Mitsubishi bomber. CW phone 300 XMTR--7.6-10.6, Rec--7.5-10.8. Plug-in crystals enable change to 2 frequencies quickly. 2 preset freq., both Xmtr. and Receiver. Trail or double wire Crystal (number of crystals--2). Poor Superhet. IF--628KC. MOPA. XTAL controlled. Fair Ant. meter provided with separate shunts on back. Same meter can be used on other Transmitters. Xmtr--1000V--DC dynamotor from 100V DC source. Receiver -250V from 12VDC source. Vibropac can power receiver if dynamotor fails. Transmitter and receiver clamped together on rack. Neon tuning indicator in transmitter antenna circuit. Provision for sidetone. No shock mounting used. Susceptible to damage by humidity and extremes of temperature. Many parts of German manufacture. Model 13. 30 96 2 1936 Naval air do 9 4.0-5.0 2 tube Aviation 3. 50 96 1 1936 do Phone only 30 Xmtr--4.2-5.0; Rec-- 4.2-5.0. 50 97 3 1937 General--Air-Naval Air-Gnd. CW phone 0.3-0.5; 5.0-10.0 Preset Number unknown. Crystal (number of crystals unknown). 5 tube superhet MOPA: 1-UX 476; 3-UV816D; 1-UV 56B. 150 96 2 1936 Air and Ground in RCN bombers. do 450 Xmtr--0.3-0.5; 5.0-10.0; Rec--5.0-10.0. do MOPA 4 tubes No intercommunication system provided for plane crew. 150 94 Not known 1934 Naval air and bombers. do 150 0.1-0.5; 5.0-10.0 Separate XTAL for each frequency used. 1 Crystal (number of crystals unknown). 6 tube Dynamotor Transmitter and Receiver mounted together on brass frame. Design sound, but not advanced. Components well made but inaccessible for servicing. 300 94 1 1934 Naval air do Xmtr--5.0-10.0; Rec-- 5.0-10.0. Not known Not known. Not known In dive bomber CW, only 7.635 and 0.458 (see remarks.) 4 plug-in crystals. 2 Crystal (number of crystals--4). Can be set up for operations as shown in "RF coverage." Alternate set of 2 crystals provided for operation on 7.435 and 16.580 MC. do 96 3 1936 Used in type 97 single seat fighter (Nate). Phone only Exact coverage unknown. Had 2 XTALS for 4.810 and 4.835 MO. Plug-in XTALS. 1 Crystal (number of crystals--1). Pretuned. Cannot be adjusted in flight. See remarks Other parts consist of combined generator and supply voltage regulator, smoothing choke assembly, remote control box, antenna selector box, and separate low frequency receiver. Parts very inaccessible for servicing. Workmanship good altho quality of parts poor. Aviation Radio No. 2. do EI Not known 1,250. Xmtr--2.&-15.0; Rec--2.5-18.0. Unknown Crystal (number of crystals unknown). 7 Stages. 2 RF, Mixer 2 IF, Det.-AVC-- BFO and Push-pull AF, Has IF XTAL Filter. MOPA Tri-tet osc. and RF Amp. Very modern, good construction Receivers do 1 D/F naval 1.76-7.5. do 2 D/F and homing 0.14-0.41; 0.55-1.5; 2.8-7.7. PY 3N do Aural and visual. 0.165-1.0 (2 bands) MO only 6 tube TRF Has 2 RF Amp. BFO and neon peak limiter. RO 4 do do 0.17-0.46; 0.45-1.2 12 tube superhet Installed in fighters and large air craft. ADF do do 0.18-2.8 (3 bands) 5 tube superhet Installed in RCN or light bomber.
Figure 360. Model 99 (1939) Type 3. Transmitter-receiver.
Close up of transmitter and receiver. Receiver at left, transmitter at right.
Figure 361. Model 96 (1936) Type 1. Transmitter-receiver model 13.
From Mitsubishi bomber. Transmitter: 7600-10600 KC. Receiver: 7500-10800 KC.
3. TELEPHONES. a. Model 92 (1932) telephone (fig. 364).
Figure 364. Model 92 field telephone.
This telephone is of conventional design and normally is used on a ground return circuit, although it may be used also on a metallic circuit. It is equipped with a buzzer and key arrangement for sending code. The complete unit is encased in a metal-reinforced, wooden box, approximately 12 inches long, 5 inches wide, and 7 inches high. Directly beneath the aluminum cover is a transmitter, handset receiver, extra single earphone, and the buzzer key. Permanent lead-in wires are fitted to the telephone to which the field wire is attached. Current is supplied by a hand-cranked generator which generates ringing current rated at 55 volts A. C. It is not advisable, therefore, to use this set with U.S. Army generators which deliver up to 90 volts A. C. It will, however, receive and transmit clearly over U.S. Army circuits, being equipped with two 11/2 volt dry cell batteries which furnish 3 volts when connected in series. These batteries normally are connected in parallel and are stored on a metal rack inside the cabinet. Compared with Allied standards, the general mechanical construction of the set is inferior. It has been found that the hand-switch on the handset receiver causes frequent cut-outs as well as noise during operation. The set is contained in a heavy leather carrying case and may be carried easily by one man. A new carrying case, composed of layers of rubberized canvas, also has been observed. This material will withstand tropical climate much better than leather. The complete set weighs approximately 12 pounds.
b. Model 2 (1942) trench telephone (fig. 365).
Figure 365. Model 2 trench telephone.
This telephone normally is used with a ground-return circuit, although it may be employed with a metallic circuit. The unit is contained in a wooden cabinet, with metal-reinforced corners. The handset; batteries; and generator, bell, condenser, and induction coil are housed in three compartments. The set may be operated on local or common battery circuits, while magneto signaling facilities also are included. The generator hand crank folds up and fits within the generator armature shaft. A fiber driving gear on the generator eliminates noise to some extent during cranking.
c. Sound-powered telephone (fig. 366).
Figure 366. Complete assembly of sound-powered telephone.
The microphone of the sound-powered telephone, deriving its energy directly from the sound waves, is a reversion to the original principle of the telephone in that the receiver unit is used also as a microphone. The instrument consists of a handset, with a single dual-purpose operating unit and an additional unit
as an extra receiver. It is used to provide intercommunication within vehicles, or over short lines when circumstances require rapid and simple setting-up and disconnection.
d. Lip microphone. This carbon type microphone is attached to a leather and elastic strap. Total weight is approximately 31/2 ounces. Other than the fact that it is used with head receivers, there is nothing to indicate for what purpose it was intended. However, since the output of this microphone is low, it is possible that it may be used in connection with radio equipment in armored vehicles.
4. SWITCHBOARDS. The Japanese have field switchboards, but in place of these they frequently connect field telephones together to form a party line system. At higher headquarters and large airfields commercial switchboards and pole lines of open wire construction have been used.
5. TELEGRAPH SETS.
Figure 367. Model 95 telegraph set with sound and buzzer.
Figure 367 illustrates the Model 95 set which can be used in conjunction with Model 92 telephone. The set has a built in key arrangement. It probably is used by lower units for administrative traffic.
6. SIGNAL LAMPS. a. Portable signal lamp.
Figure 368. Portable signal lamp. (a) Signal lamp, (b) Key with lock device,
(c) Carrying case with spare lamp, eyepieces, filters, etc.,
(d) Filters; red, amber and green, (e) Hand generator.
This lamp, provided with universal adjustment, is mounted on a tripod and powered by a hand generator. At the front, a hinged cover, equipped with a shutter adjustable to 6°, controls the intensity of light. A reflector and 6-volt lamp, rated approximately 32 candlepower, are contained inside the housing. Usually 3 different-colored filters-- green, amber, and red--are provided with each lamp. A metal-reinforced wooden cabinet, 103/4 inches long, 53/8 inches high, and 83/8 inches wide, is provided for the equipment with the exception of the generator.
b. Hand signal lamp. This small pocket lamp measures 31/2 inches long. While resembling a cylindrical flashlight, it contains no batteries; instead,
a cord, connected to an external battery, passes through the hollow wooden handle. The 3.5-volt bulb and reflector are of conventional design. Installed in front of the bulb is a glass filter, divided into red, blue, amber, and clear sectors. A cover, in front of the filter, can be revolved so that its opening will disclose a lighted segment of the desired color. Signaling is accomplished by a combination push button and slide switch on the side of the case. This lamp should be useful at short range, but the degree of security would be limited by the fact that its beam is not highly directional.
7. FIELD WIRE. The three principal types of field wire in general use are as follows:
a. Assault wire. Assault wire is very small in diameter. It consists of a single conductor and is composed of 8 strands (1 copper and 7 steel) with an outer covering of yellow-colored braid. This wire is for ground-return circuits and is used between regiments and forward units.
b. Seven-strand wire. This single conductor, 7-strand wire (3 copper and 4 steel) is larger in diameter than assault wire. The wire is rubber insulated, and tests have shown that the insulation resistance can remain high throughout a 14-day immersion period. It has an outer covering of yellow colored braid. Tensile strength of the wire is high, but its abrasion resistance is low, and its electrical characteristics are not as good as indicated by its construction. This wire is for ground-return circuits and is used between regimental and battalion headquarters.
c. Heavy wire. Heavy wire, consisting of two rubber-insulated, solid conductors (one black, the other red), is used for metallic circuits, probably between division and higher headquarters as well as at the larger airfields. It has an outer covering of green-colored braid.
Different types of cables are used by the Japanese for various purposes. Figures 369 and 370 show types used and their characteristics.
9. WIRE REEL UNITS. The Japanese use various types of hand wire reel units, most of which appear to be designed primarily for handling single conductor wire.
a. Hand wire reel unit.
Figure 371. Hand wire reel unit with broomstick handle.
The reel is carried on the shoulders, or to one side of the body, by means of a broomstick handle and it will hold approximately 1,600 feet of the larger diameter, yellow-braided, field wire. No crank is provided for convenient recovery of the wire. Perforations on the head and splines of the drum tend to damage the insulation if the wire is stored on the reel for any length of time. This unit, which is light in weight and not very rugged, can readily be dismantled without the use of tools. (See fig. 371.)
b. Head wire reel.
Figure 372. Head wire reel--used by field artillery. At left: Recovering wire. At right: Reeling out wire.
The unit (see fig. 372) is solidly made of pressed metal, with leather straps for carrying on the chest or back. This reel evidently is designed for use by troops in forward areas and normally is carried on the back to allow free use of the hands. (See fig. 372.) When recovering wire, for which purpose a handle is provided, the reel normally is carried on the chest. The reel may be folded up when not in use.
10. AIRPLANE PANELS. Cloth air-ground panels are usually 11/2 to 3 feet wide and 61/2 to 13 feet long. Some shorter panels, and some triangular panels 3 to 61/2 feet on each side, have been used. In most cases panels are white, but other colors, contrasting to the terrain, also may be used. When regular panels are not available, rags, maps, or pieces of paper may be substituted. On occasion, Japanese soldiers have been observed to lie on the ground to form panel signals.
|Outside Diameter (inch)||Cross section of cable||1||2||3||4||5||6||7||8||9||Remarks|
|7/16.||Rubber insulation.||Rubber insulation.||Cotton string wrapping||No. 14 Stranded wire.||This was taken from the power cord of a test lamp. It corresponds to ordinary rubber covered lamp cord.|
|7/16||Woven steel wire sheath (lead).||Impregnated cloth.||Impregnated paper.||Lead sheath||Cotton cloth wrapping.||Rubber insulation.||Copper wire core.||The conductor of this cable consists of IP strands of No. 20 copper wire. Probably used as buried underground cable.|
|7/16||Lead sheath||Cotton cloth||Jute or hemp cord filler.||Silk cloth||Rubber insulation.||Solid copper wire.||Each of the three conductors is composed of No. 17 solid copper wire.|
|7/16||Lead sheath||Cotton cloth||Rubber insulation.||Stranded copper wire.||This was taken from a Japanese radar transmitter and was used to carry power to the tube filaments. The single conductor core consists of 30 strands of No. 20 copper wire.|
|3/8||Lead sheath||Cotton cloth||Rubber insulation.||Solid copper conductor.||This was used to carry 600 volts to a radar transmitter. The solid copper conductor is size No. 14.|
|9/32||Black cotton cloth.||Woven steel wire sheath.||Rubber insulation.||Air holes in rubber.||Solid copper conductor, size No. 23.||The cloth covered coaxial line is used to carry video and pulse signals between the various units of a radar. The estimated impedance of the line is 100 OHMS. The capacitance of the cable has been decreased by extruding three holes in the otherwise solid rubber dielectric. These holes are in a symmetrical position around the center conductor.|
|Outside Diameter (inch)||Cross section of cable||1||2||3||4||5||6||7||8||9||Remarks|
|11/4||Tar coated hemp||Spiral wound steel band sheath.||Impregnated fiber||Lead sheath||Impregnated paper.||Impregnated paper.||No. 10 solid copper wire.||15 conductors of No. 17 solid copper wire.||This cable is probably used as underground power cable.|
|11/6||White rubber insulation.||Cotton string filler.||5/16" diam. stranded from No. 31 tinned copper wire.||Rubber insulation.||Rubber insulation for H. V.||No. 9 stranded wire from No. 30 tinned copper wire.||This cable is probably used to carry power from a power supply unit to a communications transmitter. The large wires are for the filament power and the small are for B plus and bias voltages.|
|29/32||Lead sheath||Brown paper||Copper sheath||Brown paper||Polystyrene spacers every inch.||Copper No. 9 wire (solid).||The shielded balanced wire line is used to carry r-f power to the antenna of a Japanese Radio Navigation Aid. The characteristic impedance of the line is approximately 115 OHMS.|
|11/16||Woven steel wire sheath (white).||Impregnated cloth.||Impregnated paper.||Lead sheath||Cotton cloth||Jute or hemp cord filler.||Silk cloth winding.||Rubber insulation.||Solid copper conductor.||This is a nine conductor cable. Probably multi-conductor remote control cable. All the conductors are size No. 17.|
|1/2||Lead sheath||Cotton cloth||Black rubber insulation.||White rubber insulation.||Stranded copper||This high voltage cable was used on a radar transmitter to carry plate voltage at a potential of 6KV. The stranded core, which is size No. 11, is made up of seven strands of No. 20 copper wire.|
|7/16||Rubber insulation.||Cotton string filler.||Rubber insulation.||No. 16 stranded copper wire.||This is probably ordinary power cable.|
11. SIGNAL FLAGS. Two small hand flags, one red and the other white, are used for semaphore. For signaling Morse Code a large red and white flag, on a bamboo shaft about 5 feet long, is utilized.
12. MILITARY DOGS. Trained dogs, used to some extent for carrying messages, are cared for and trained by the division signal unit.
13. PIGEONS. Pigeons, also, are used for carrying messages.
14. HAND GENERATORS. a. Model "F".
Figure 373. Model "F" hand generator right side view--showing crank handle in place.
This simple and compact hand-driven generator, which weighs only 16 pounds, delivers 24 watts. It serves as a source of filament voltage (3 volts) and of plate voltage (125 volts). The mechanical transmission between driving handle and armature consists of 4 geared wheels, 2 of which are fiber, the others steel. According to the name plate, the normal rate of turning is 70 revolutions per minute, giving an armature speed of 5,200 revolutions per minute. Harness is provided for carrying the generator and for fastening it to a support. It is possible for a man to work the generator when the straps are slipped over his shoulders, with the base resting against his chest.
15. BATTERY CHARGER. Two charging circuits are provided. One uses a Tungar, half-wave rectifier, delivering 14 volts at 6 amperes. The other circuit uses a type 83, mercury-vapor, full-wave rectifier, delivering 130 to 160 volts at 0.1 ampere. Component parts are mounted on an angle-iron framework which fits into a metal carrying case. The case is provided with ventilating apertures, 3 weatherproof receptacles, a door at the rear, and a leather carrying handle. The charger is capable of charging one 12-volt storage battery and one storage "B" battery at an average efficiency of 30 percent. This efficiency compares favorably with that of half-wave Tungar chargers of American manufacture. The switching arrangement controlling the active turns in the transformer primaries allows operation of the charger from three different line voltages.
Figure 374. Battery charger, front view, showing controls.
16. POWER UNITS--DUAL VOLTAGE DC (1300V/12V). This is a completely self-contained, rope-starting, power unit, consisting of a single cylinder of 1.977-inch borex2.0-inch stroke. The air-cooled gasoline engine is coupled directly to a straight-shunt, 2-pole-field, dual-voltage 1300-V/12V generator, inclosed in an aluminum housing. Engine and generator are ruggedly constructed and supported, indicating long-life operation. This unit can be used to furnish plate voltage to U.S. Army SCR 177.
Figure 375. Dual voltage (1300V/12V) DC power unit.
17. PYROTECHNIC SIGNALS. The Japanese make much use of pyrotechnic signals. Projection is achieved by means of Models 10 and 89 Grenade Dischargers, both of which are common infantry weapons.
Listed below are some of the pyrotechnic signals which can be used in grenade dischargers. They frequently have been referred to by the Japanese as dragons. The nature of the signal may be ascertained by two methods: (a) by color bands painted on the body, (b) by designs embossed on the cover (for use in the dark).
Signal Color bands on body Black smoke, parachute One wide black band. White star, parachute One wide white band. White star One narrow white band. White star, double Two narrow white bands. White star, triple Three narrow white bands. Orange smoke, parachute One wide yellow band. Green star, parachute One wide green band. Green star, single One narrow green band. Green star, double Two narrow green bands. Red star, parachute One wide red band. Red star, triple Three narrow red bands.
Signal pistol, 35-mm (1.38-inch) parachute and cluster "stars" in red, white, or green colors, with a burning time of from 4 to 15 seconds, are reported to exist. The cartridge closely resembles a shotgun shell. Model 97 (1937) signal pistol: One and three barrel models of this newer type signal pistol have been reported. The pistol is well made of a good grade of steel with an excellent finish; its overall length is 9 13/16 inches, and its weight is 1 pound 13 ounces.
Section V. ENGINEER EQUIPMENT
1. GENERAL. a. Japanese engineers are well-equipped and are armed as infantry. They have shown outstanding ability in both the construction and demolition of bridges. On the other hand, airfields and roads so far encountered have not been up to Allied standards in speed of construction or serviceability. This may be attributable to the fact that the Japanese have depended more on manual labor than on heavy equipment, which they have not taken into forward areas in any quantity.
b. The construction of field fortifications has been very highly developed, and even at remote points Japanese engineers have been successful in constructing first class defense positions from material immediately available. (For detailed descriptions of various kinds of Japanese defensive constructions, see part 2, secs. III and IV, chapter 7).
c. Engineers are also well-equipped with a wide variety of explosive charges and other material for assault and demolition tasks.
d. The shipping engineers (Sempaku Kohei) are specially trained and equipped to operate a large
Figure 376. Pyrotechnic signal for use in grenade dischargers.
Figure 377. 35-mm (1.38-inch) signal pistol.
Figure 378. Model 97 signal pistol with various types of signal cartridges.
variety of transport craft, including landing barges. (For a chart showing specifications of all known types of Japanese landing craft, see chapter 8, >fig. 157).
e. Pictures and detailed descriptions of certain items of engineer equipment will be found on the following pages.
2. AMPHIBIOUS EQUIPMENT. a. Bridges. (1) Assault bridges. Several different models have been developed and standardized. Two types are illustrated in figures 379 and 380. One type is made of lengths of steel tubing, supported by bags filled with kapok. The sections are joined together and afterwards locked. They are light enough to be carried easily by foot soldiers. Crossings of streams 100 feet and more in width are reported possible with this type of bridge.
The foot bridge illustrated in figure 380 is supported by floats, each of which can be carried by one foot soldier. This type is for infantry only.
(2) Ponton bridges. The heavier bridge is suitable for artillery and heavy equipment. The boats which support it are of standard sizes, especially developed for this work. One type, designed for transport by wagon, has 2 bow sections, each 8.7
Figure 379. Assault bridges for infantry.
Figure 380. Small ponton bridge.
feet long, and 2 center sections, each 7.1 feet long. This boat weighs 1,650 pounds complete. An even larger boat of this type, which also comes in 4 sections, is 45 feet long and weighs 6,800 pounds complete. Another type is designed for packing by horses; it has 2 bow sections, each 4.4 feet long, and 3 center sections, each 4 feet long. The complete boat weighs 921 pounds, and is slightly over 20 feet in length. An even lighter version also exists.
(3) Improvised trestle bridges. The Japanese are skilled in the construction of wooden trestle bridges (fig. 381) which they erect with great rapidity from materials prepared beforehand or available locally. Joints usually are lashed with straw rope, and occasionally are strengthened with iron pins. Such trestles are found serving as approaches to ponton bridges in wide river beds; in shallow rivers they may be several hundred feet in length. Despite their flimsy appearance they are capable of supporting artillery and other heavy equipment.
Figure 381. Improvised trestle bridge.
(4) Sectionalized steel bridges. Prefabricated steel bridges are used by the Japanese, but not as widely as by some other Armies. One truss-construction, portable, steel bridge is 48 feet long and weighs 820 pounds.
b. Assault boats. (1) Collapsible boats. Several types of collapsible boats have been developed. One of these, model F (fig. 382) is an outstanding example of assault boat design, and is very widely utilized. The boat, divided into two sections, each of which collapses flat on itself, (fig. 383) is individually floatable. Each section is 13.6 feet long, 4.75 feet wide, and 2.18 feet high. The wooden frame is braced, and all joints are bonded with rubber. The boat will hold 20 men, and it is estimated that 9 such boats could be loaded flat on a 2 ton truck. Light outboard motors have been used to propel this boat. Three types of rubber (pneumatic) boats, of from 1- to 10-man capacity, are in use. These are similar in construction to the rubber boats used by other Armies.
Figure 382. Model F, collapsible assault boat.
Figure 383. Half of collapsible assault boat, model F, completely folded.
(2) Demountable boats. Japanese engineers also operate a variety of demountable motor boats, fitted with outboard and inboard motors of various kinds. One small, 30-foot boat breaks into 4 sections and is propelled by an outboard motor. Some of the outboard motors are arranged for animal pack. Another larger type breaks into only 2 sections; the stern section is fitted with a 4-cylinder, inboard gasoline engine of 30 horsepower. It is
not believed that any of these demountable boats permanently mount any weapons.
c. Landing barges. (1) Japanese engineers operate a large variety of landing barges, which have been employed extensively in various theaters. Since Allied air superiority has seriously interfered with Japanese use of transports in many theaters, landing barges generally have been employed for the supply and evacuation of their forward areas. As many as 500 of these craft have been found congregated in one port.
(2) Some of the design features of these small vessels are of interest. The landing-barge screw shown in figure 384 is designated for operation in shallow waters and affords maximum protection to the screw. The Japanese generally are credited with the development of the folding ramp, which now is used so extensively.
Figure 384. Landing barge screw.
(3) A typical landing barge is the Daihatsu Model A (Army). This Daihatsu is probably in wider use than any other type; the picture in figure 385 gives a general idea of it.
Figure 385. Daihatsu model A (Army) landing barge.
Figure 386. Daihatsu model A landing barge, showing armor plate protecting controls.
Figure 387. Yamasen model E flat-bottom landing barge.
[Photos only -- have been integrated with text.]
[Photos only -- have been integrated with text.]
(4) The specifications of the Daihatsu illustrated in figure 385 are as follows:
Length 49 feet (approximately). Beam 11 to 12 feet. Height 6.5 feet (approximately). Draft 3 to 4 feet. Freeboard 1.5 to 2 feet amidships. Speed 6 knots (cruising (10 knots maximum) empty). Engine Diesel, 6 cylinder, 60 to 80 horsepower, preferred. Some may have heavy oil, electric ignition, or gasoline engines. Capacity 100 to 120 men (short hauls only) 40 to 50 men on longer trips, or 10 to 15 tons, or 1 light tank (7 to 9 tons), or 1 150-mm howitzer (6 to 7 tons, complete). Crew 5 to 7 men. Armament Not standardized. However, at least two machine guns, or one or two 13-mm heavy machine guns. Fire from 20-mm guns has been encountered from this type, and on several occasions 37-mm guns have been found. Armor A vertical shield of steel,.12 to.36 inch thick, usually protects the coxswain and control gear from frontal fire. Occasionally this type has steel plates, 15 inches by 12 inches,.36 inch thick, hooked to the gunwales. Construction Based on standard Japanese fishing boat design, this landing barge has been developed over a long period of years. The metal hull, about.2 inch thick, is of welded steel plate, supported by heavy wooden braces. The twin keels at the bow are of heavier steel and are riveted. The bow ramp is of wood, and the sides above the waterline are covered with timber. The Daihatsu has an open cockpit in the middle, with a watertight compartment at each end. The engine room at the rear is steel decked.
This clumsy looking vessel is surprisingly versatile, and will stand a great deal of abuse. Its heavy, double-keeled bow and protected screw make it very serviceable in shoaly, rock-infested waters.
3. CONSTRUCTION EQUIPMENT. a. Rollers. Various types of road rollers, of small, medium, and large sizes, have been encountered. All are of simple and sturdy design. The small roller shown in figure 388 weighs about 9 tons and is powered with a Ford model B, 4-cylinder, gasoline engine. The medium roller shown in figure 389, about 18 tons in weight, is Diesel powered. Larger rollers also have been captured.
Figure 388. Small gasoline roller.
Figure 389. Medium Diesel-powered roller.
b. Prime movers. For detailed specifications, see section III of this chapter.
c. Power rock crushers. Power rock crushers of rather small capacity, but of good construction, have been seen. Power is furnished by small Diesel motors. These rock crushers are found mounted in pairs, usually on a platform.
d. Concrete mixers. Portable concrete mixers (fig. 390) of various types have been developed by Japanese engineers. The mixers, some of which are Diesel-powered, can be moved easily from one job to another and erected on a platform to facilitate pouring. Some army types are mounted permanently on trucks.
Figure 390. Diesel-powered concrete mixer.
e. Portable railroads. Japanese engineers make extensive use of portable railroads of various kinds. One standardized type has a gauge of two feet. Rails are small in section, weighing about 10 pounds per foot, and are 18 feet in length. They usually are laid for temporary use. Switch sections are prefabricated. Light flatcars, 4 feet wide and 6
feet long, are used on this type of portable railroad. Racks or sideboards can be fitted to give increased capacity to the flatcars. Such light cars can be pushed by manpower, or pulled by small, gasoline-powered locomotives.
f. Mobile power driven saw. The power saw is another piece of Japanese construction equipment used in forward areas, where defenses must be constructed of heavy logs. Power is furnished by a small gasoline motor. In rear areas, larger circular saws, permanently installed and driven by belt from Diesel motors, will be found.
g. Mobile well driller. The heavy, mobile, power-operated well driller is used in favorable terrain. Power is furnished by the truck engine, which drives an air compressor connected with a large compressed air tank.
h. Miscellaneous construction equipment. A wide variety of miscellaneous equipment for construction of bridges, defense works, roads, and airfields has been developed by Japanese engineers. In the forward areas so far overrun, however, main reliance has been placed on labor troops rather than on mobile equipment. Moreover, it is felt that Japanese engineers have not developed prime movers and earth-moving equipment of the heaviest variety, although medium-weight equipment of these categories has been identified.
4. MAINTENANCE EQUIPMENT. a. Electric power units. Electric generating units, both mobile and heavy, usually Diesel powered, are in wide use. They usually are of standard design and are utilized to supply light and power for a variety of purposes. On one island fortress, Diesel-powered generator units ranged from 20 to 100 KVA, all 2,300 volts, 3-phase, 50-cycle. Underground cables led to intermediate transformer vaults, where the current was stepped down to 110/220 volts for consumption by gun-turret motors
[Photos only -- have been integrated with text.]
and communications equipment. Searchlights were DC arc type, with motor generator converters. A large number of battery-charging panels served to charge batteries for communication equipment.
b. Ice plants.
Figure 391. Field ice plant.
Ice plants of varying capacities have been found on several islands occupied by the Japanese. These are well-constructed (fig. 391), and some of them have been used by our troops for long periods.
5. DEMOLITION EQUIPMENT. Japanese demolition equipment is similar to that of other Armies, but unusual attention has been given to small demolition charges employed in assault tasks. Much use is made of picric acid, and serious efforts have been made to preserve this compound from moisture. Plastic explosives also have been used by the Japanese for some time. Although electric detonators have been well developed, the Japanese take a very practical view of equipment of this nature, and therefore have retained friction-type igniters in many instances because of their simplicity.
a. Small charges. In addition to those described in section I, chapter 9, a variety of small charges, in either block or cylindrical form, are available. Picric acid, TNT, and toluol cheddite (Ammonium perchlorate 76 percent) are used in these charges, some typical specifications of which are as follows:
(1) Block charges. Length 2.8 inches. Width 1.6 inches. Thickness 2 inches. Weight Picric acid and TNT.44 pound. Toluol cheddite .42 pound. (2) Cylindrical charges. Length 4.6 inches. Diameter 1.2 inches. Weight Picric acid and TNT.22 pound. Toluol cheddite .20 pound.
There are several containers for these small charges. One zinc can, wired for an electric detonator, has the following specifications:
Length 8.2 inches. Width 2.2 inches. Thickness 3 inches.
This can contains three of the block charges mentioned in (1) above and is very widely used.
b. Large charges. In addition to the bangalore torpedo described in section IV, much larger demolition charges in this form are used by engineers. One large bangalore torpedo consists of 4 sections and a detonator. Each section contains 10 of the cylindrical charges described in a (2) above. The
assembled torpedo is 34 feet long and weighs 225 pounds. Other large charges are assembled in various forms as needed, with the addition of plastic explosive when necessary.
c. Plastic explosive. This explosive has the following composition:
Cyclonite 80 percent. Vegetable oil binder 20 percent.
It is issued in rolls, 4 inches by 1.12 inches, each roll weighing .25 pound. These rolls are individually wrapped in parchment and in turn wrapped in a paper package.
d. Detonators. (1) Nonelectric. Several types have been recovered. One very large, non-electric detonator has the following specifications:
Length 2.7 inches. Diameter 0.3 inch. Contents Fulminate of mercury 88 grams PETN--4 grams.
This detonator is made of brass.
(2) Electric. There are a number of types and sizes. Model 97 (1937) electric detonator has outer and inner cases, both of brass, and has the following specifications:
Length 3.25 inches. Diameter 0.27 inch. Contents Fulminate of mercury -- 3.93 grams, fulminate of mercury plus a
deadening agent--0.28 grams. PETN--1.98 grams.
These detonators, each individually wrapped, are packed 10 in a waxed cardboard box. inside a metal container. Such detonators may be used with electric blasting machines, of which a variety are available.
(3) Pull igniters. These are very widely employed. One type consists of a brass body, with a red plastic outer sleeve. One end of the screw can is fitted with an eye for attaching a trip cord. Attached to the inside of the cover is a short pull string which projects through a small pellet of friction ignition composition. When the sanded end of the string is drawn through the pellet, it ignites and flashes through the igniter body. The assembled igniter is 2.75 inches long, and.30 inch in diameter.
(4) Several types of slow burning and instantaneous fuzes have been developed. The instantaneous type (Primacord) is protected by a rubber-impregnated, hemp thread cover.
6. SURVEYING, MAP-MAKING, AND REPRODUCING EQUIPMENT. Japanese transits, theodolites, map-scribers, and reproducers are of good quality and workmanship. In design and development the Japanese have closely followed or even duplicated European or American patterns, and calibrations and markings usually are in Arabic numerals. Allied engineers have no difficulty in making good use of these instruments in the field.
Section VI. CAVALRY AND RECONNAISSANCE
1. GENERAL. The Japanese have given much thought to the cavalry arm, which is particularly useful in Manchuria and North China. Their specially bred cavalry horses, the get of Anglo-Arabian sires and native mares, average about 14.3 hands (approx. 57 inches). They have proved satisfactory, since they are sturdy, enduring, and relatively speedy.
Figure 392. Standard cavalry saddle.
The saddle (weight about 46 pounds with saddle bags, etc.) shows evidence of both English and American design (fig. 392).
The saber is a combination of a European type hilt with a Japanese cutting blade. It is 40 inches in length and weighs 3.13 pounds (fig. 393).
Figure 393. Standard cavalry saber.
4. OTHER EQUIPMENT. a. The individual trooper carries model 44 (1911) 6.5-mm cavalry carbine. (See sec. II, chap. 9.) The horse artillery of the cavalry brigade is armed with a 75-mm field gun, which is a variation of model 38. It is possible that model 95 (1935) 75-mm field gun also is used by these units. Light and heavy machine guns are standard equipment of cavalry brigades.
b. The Japanese have formed reconnaissance units which contain both mounted troops and motorized units. In these latter units, tankettes, and possibly armored cars (see sec. IV, chap. 9) will be found. Personnel of such units are armed like the horse troops, except that the saber may be omitted.
Section VII. AUTOMOTIVE AND LAND TRANSPORT EQUIPMENT
1. GENERAL. a. Although the automotive manufacturing industry was comparatively new in Japan, considerable progress had been made by the end of 1941. Both Ford and General Motors had maintained large assembly plants in Japan proper for many years, and very large numbers of the trucks produced by these plants naturally are used now by the Japanese Army. In addition, very large numbers of European and American motor vehicles were captured by the Japanese in their advance southward.
b. All motor vehicles manufactured in Japan are right-hand drive. They have comparatively high ground clearance and small turning radii. The Diesel is the preferred power unit for heavy vehicles, and many are so fitted. Power-weight ratios generally are not good, and tires often are overloaded. Power take-off systems of various kinds often are
found. Hydraulic foot brakes were not installed until recent years; many vehicles still are equipped with mechanical brakes. Because of local regulations, the emergency, or handbrake, is always entirely separate from the main braking system and is mechanically actuated.
c. Because of gasoline shortages, charcoal and wood gas producers began to be installed in 1937. By 1942, all non-military vehicles had been converted to their use, and it seems probable that many military vehicles now operating in Japan proper are using self-generating fuel systems.
2. PASSENGER CARS. a. Japanese model 95 (1935) 4x4 scout car.
Figure 394. Japanese model 95 (1935) 4x4 scout car.
This lightweight, unarmed, reconnaissance vehicle (fig. 394) was developed after the Manchurian Incident, when the need for an all-purpose scout car became pressing. Its air-cooled engine offers many advantages for operations in Manchuria and North China, where very low temperatures often are experienced. Initial difficulties with the four-wheel drive, particularly with the front universal joints, are believed to have been overcome. Special tires, with heavy rubber lugs, are provided for exceptionally difficult terrain.
Specifications General: Weight 2,310 pounds, complete. Length 134 inches. Width 60 inches. Height 66 inches. Clearance 9 inches. Tread 50 inches. Wheelbase 79 inches. Engine: Type 4 cycle, gasoline, air-cooled. Number of cylinders. 2, set at 45 degree angle. Horsepower Maximum. 33 at 3,300 r.p.m. Compression ratio. 5 to 1. Fuel capacity 13 gallons. Chassis: Final drive reduction. 6.83 to 1. Transmission Selective, standard, 3 forward and 1 reverse. Brakes Mechanical; service, external contracting; emergency,
internal expanding on driveshaft.
b. Standard Nissan 5 passenger sedan.
Figure 395. Standard Nissan 5-passenger sedan.
First produced in 1937, the Nissan (fig. 395) has
[Photos only -- have been integrated with text.]
[Photos only -- have been integrated with text.]
had several modifications, but no major improvements. The design, and the tools to make it, were purchased from the Graham-Paige Co., which designed and tooled up for this model in 1935. but never went into production. The design is not remarkable in any way; from modern standards the power-weight ratio is poor.
Specifications General: Weight 3,108 pounds. Length (overall) 186 inches. Width 67.5 inches. Height 69 inches. Wheelbase 110 inches. Clearance 8 inches. Tread 56.5 inches. Engine: Type 4 cycle, gasoline, 6 cylinder, "L" head (Side valve).
This possibly might be replaced by the Toyoda engine,
an overhead valve type which is an exact copy of 1939 Chevrolet.
Horsepower 85 maximum. Bore 82-mm (3.23 inches). Stroke 114-mm (4.49 inches). Displacement 3,670-cc (224 cubic inches). Compression ratio 6.5 to 1. Electric system 6 volts. Chassis: Final drive reduction 4.09 to 1. Transmission Selective, standard shift, 3 forward, 1 reverse. Brakes Hydraulic; emergency is mechanical, internal-expanding on driveshaft.
c. Model 93 (1933) Staff car.
Figure 396. Model 93 (1933) staff car.
This 6-wheeled staff car (fig. 396) was developed over a period of years. Originally, Hudson and Studebaker chassis were used, but a Japanese chassis ultimately was developed. Available specifications indicate a poor power-weight ratio, and a performance not comparable with that of any U.S. command car. However, this vehicle has not yet been reported from the field, and improved models may exist.
Specifications General: Weight 5,720 pounds. Length (over-all) 17 feet 8 inches. Width (over-all) 6 feet 4 inches. Height (over-all) 6 feet 6 inches. Wheelbase 8 feet 11 inches. Clearance 11 inches. Tread 5 feet 1 inch. Engine: Type Gasoline, 6 cylinder, "L" head (side valve) water-cooled. Horsepower 68 maximum. Bore 90-mm (3.54 inches). Stroke 115-mm (4.53 inch). Displacement 4,790-cc (292 cubic inches). Compression ratio. 5.1 to 1. Electrical system. 12 volts. Chassis: Final drive reduction. 5.25 to 1. Transmission Standard, 4 forward 1 reverse. Brakes: Foot Mechanical, expanding type. Emergency Mechanical, contracting type.
3. TRUCKS. a. Model 94 (1934) 6x4 truck.
Figure 397. Model 94 (1934) 6x4 truck.
The development of this chassis (fig. 397), in which the rear 4 wheels drive and the 2 front wheels only steer, has been progressing for more than 15 years. In recent years, an attempt has been made to distribute this vehicle to commercial users, and prior to 1941 a substantial subsidy was paid to private purchasers. Initial difficulties with the final drive now have been overcome, and the vehicle is reliable, although the power-weight ratio is not good. Ground clearance is unusually high, and one or more auxiliary transmissions can be fitted. More powerful Diesel engines than those mentioned in the specifications now may be in use. The chassis of the Model 94 is the basic one for the Japanese Army's armored car.
Specifications General: Type A (gasoline) Type B (Diesel) Weight 7,500 pounds 8,170 pounds. Length 17 feet 8 inches* 17 feet 8 inches. Width 6 feet 2 inches 6 feet 2 inches. Height 7 feet 4 inches 7 feet 4 inches. Wheelbase 9 feet 2 inches 9 feet 2 inches. Clearance 11 inches 11 inches. Tread 4 feet 11 inches 4 feet 11 inches. Engine: Type Gasoline, 6 cylinder "L" head
(side valve) water-cooled.
Diesel, 4 cylinder. Overhead valve,
Horsepower 68 maximum 70 maximum. Bore 90-mm (3.54 inches) 105-mm (4.13 inches). Stroke 115-mm (4.53 inches) 140-mm (5.51 inches). Displacement 4390-cc (268 cubic inches) 4850-cc (296 cubic inches). Compression ratio 5.25 to 1 17 to 1. Electrical system 12 volts 12 volts. Chassis: Final drive reduction 8.33 to 1 6.75 to 1. Transmission Standard, 4 forward, 1 reverse Standard, 4 forward, 1 reverse. Brakes: Foot Mechanical, expanding Mechanical, expanding. Hand Mechanical, contracting Mechanical, contracting. * Truck shown in figure 397 measures 16 feet 3 inches long.
[Photos only -- have been integrated with text.]
b. Model 97 (1937) Nissan 4x2 cab-over-engine truck. The original model, produced in 1937, was a combination of Graham-Paige and Japanese designs. The cab-over-engine design was adopted because of the narrowness of Japanese roads. The whole front axle assembly proved to be too light, however, and great difficulty was encountered in maintaining the alignment of the front wheels to prevent excessive tire wear. An improved model of more conventional design was finally developed, but a very large number of the original models still are being used by the Japanese Army. The power-weight ratio of the Model 97 is not good.
Specifications (104 inch Wheelbase model) General: Weight 2,880 pounds. Length (chassis) 169.5 inches. Width 80 inches. Height Wheelbase 104 inches. Clearance 91/2 inches. Tread 54.7 inches. Maximum speed 50 miles per hour. Engine: Type Gasoline, 6 cylinder, "L" head (side valve) water-cooled. Horsepower 85 maximum. Bore 82-mm (3.23 inches). Stroke 114-mm (4.49 inches). Displacement 3670-cc (224 cubic inches). Compression ratio 6.5 to 1. Electrical system 6 volts. Chassis: Final drive reduction 6.19 to 1. Transmission Standard, 4 forward 1 reverse. Brakes: Foot Hydraulic. Hand Mechanical.
c. Model 1 (1941) 4x2 Toyoda truck.
Figure 398. Possible Model 1 (1941) 4x2 Toyoda truck.
After disastrous experiments with a truck of their own design, the Toyoda Company finally produced this model (fig. 398), almost an exact copy of the 1939 Chevrolet.
Some manufacturing difficulties have been encountered, and the present power-weight ratio is not considered satisfactory.
Specifications General: Weight 5,500 pounds. Length 18 feet 10 inches. Width 6 feet 4 inches. Height 7 feet 5 inches. Wheelbase 15 feet 6 inches. Clearance 9 inches. Tread 6 feet 1 inch. Engine: Type Gasoline, 6 cylinder, "L" head (side valve) water-cooled. Horsepower 78 maximum. Bore 3.31 inches. Stroke 4.00 inches. Displacement 206 cubic inches. Compression ratio 6 to 1. Electrical system 6 volts. Chassis: Final drive reduction 6.167 to 1. Transmission Standard, 4 forward 1 reverse. Brakes: Foot Hydraulic. Hand Mechanical.
4. TRAILERS. a. Model 94 (1934) 3/4 ton tracked trailer.
Figure 399. Model 94 (1934) 3/4-ton tracked trailer.
This trailer (fig. 399) has been designed especially for towing behind the various model tankettes. In China, it has been used extensively for transportation of supplies and ammunition. The body of the trailer appears to be of pressed steel construction, and the suspension consists
[Photos only -- have been integrated with text.]
of 2 bogie wheels with front and rear idlers. Track is similar to that used on the tankette.
b. 2-wheel trailer.
This 2-wheel trailer (fig. 400) is designed especially for high-speed transport. It is of metal construction and is equipped with pneumatic-type tires.
Figure 400. 2-wheel trailer.
5. MOTORCYCLES. a. Model 97 (1937) motorcycle.
Figure 401. Model 97 (1937) motorcycle.
Japanese military motorcycles (fig. 401) are adaptations of Harley-Davidson designs. Several models, between 1,000-cc and 1,500-cc displacement, have been produced, but it is believed that model 97 is generally in use. Extra large wheels can be fitted to obtain maximum ground clearance. The design of all types includes provision for a sidecar, which can be fitted with a light machine gun for which at least two different mounts are available. Only minor changes have been made in the original Harley-Davidson designs, and performance is generally satisfactory.
Specifications General: Weight 1,100 pounds. Length 8 feet 6 inches. Width w/sidecar 5 feet 11 inches. Height 3 feet 10 inches. Wheelbase 5 feet 3 inches. Clearance 8 inches. Tread 4 feet 1 inch.
Specifications --Continued Engine: Type Gasoline, air-cooled, 4 cycle. Cylinders 2, set at 45 degree angle. Horsepower 25 maximum. Bore 90-mm (3.54 inches). Stroke 94-mm (3.70 inches). Displacement 1196-cc (73.0 cubic inches). Compression ratio. 4.8 to 1. Electrical system. 6 volts. Chassis: Transmission 3 forward, 1 reverse. Brakes Mechanical.
b. Motor tricycles (Sanrinsha).
The motor tricycle (fig. 402) has been developed as a commercial freight carrier in Japan since 1930. Many commercial versions exist, with engines ranging from 350 cc to 1,000 cc in displacement. Lighter types have single-chain drive without differentials, whereas heavier types may have shaft or double chain drive, with differentials. Load capacities vary from 300 to 1,000 pounds. A standard three-speed transmission, and reverse, is used. It is believed that the Army adopted whatever types were available, and that no standard army model exists. Lighter motor tricycles may have 2-cycle engines, and some 2-cylinder types have been encountered. The usual design, however, is chain driven, with a slow-speed, single-cylinder, 4-cycle engine of about 750-cc displacement.
Figure 402. Motor tricycle.
Specifications Length 9 feet 6 inches. Width 4 feet 1 inch. Wheelbase 6 feet 2 inches.
6. BICYCLES. Japan is one of the world's largest producers of bicycles; in 1940 there were 1,000,000 in Tokyo alone. There is a standard army type, designed along English lines, with front and rear wheel brakes and large wheels. It has been used extensively in the present war.
7. TRANSPORT CARTS. The Japanese Army employs a variety of hand- and horse-drawn carts. Several of these are shown in figures 403, 404, 405.
Figure 403. Army transport cart of wooden construction with metal bracing.
It weighs 350 pounds and has a reported capacity of 400 pounds.
A modified type has chassis springs.
Figure 404. Transport cart designed to be towed by 2 draft horses.
It weighs 765 pounds and has a reported carrying capacity of 825 pounds.
Figure 405. Collapsible hand cart of metal construction weighing 100 pounds.
It may be pulled by hand or towed by bicycle.
Section VIII. TENTAGE
1. GENERAL. Although the Japanese have excellent octagonal tents, very little use is made of tentage in training or in the field, aside from shelter-half tents. Tents are considered necessary only for medical units and field hospitals, or for troops in regions where other shelter is not available. In inhabited regions, troops are billeted in houses or other buildings; in jungles, native huts frequently are built as soon as the situation becomes sufficiently stabilized. The Japanese are unable to improvise shelters in cold barren regions and therefore house large numbers of men in tents. Even there, every effort is made to bring forward building materials in order to get the men from under canvas as soon as possible.
a. Octagonal tent.
Figure 406. Japanese octagonal tent.
(This complete tent weighs 118 pounds, without pegs and poles.)
The octagonal tent ordinarily houses from 15 to 20 men, although the manual states that 40 can be accommodated in the tropics and 36 in cold regions (fig. 406). Pyramidal in shape, it is made of comparatively lightweight, closely-woven duck. It is about 24 feet in diameter and uses a 12 foot 9 inch center pole.
b. Use of the octagonal tent in cold climates. (1) In cold regions a second tent of closely-woven, strong, white cotton is suspended inside the main tent and held in place by tie-tapes. The 6 to 8 inches of air space between the tent and tent liner gives good insulation against the cold, eliminates drafts, and provides a second shelter against moisture. Such a tent may be heated efficiently and economically because of these double walls which also permit the use of dim lights at night without danger of violation of blackout discipline.
(2) Two types of stoves are used in these tents, both with grates for burning coal or charcoal. One is a drum stove, 20 to 22 inches in diameter and 24 inches high, with a 6 inch opening in the center of the top for the stovepipe. The second type of stove is cast iron, about 2 feet high, 18 inches deep, and 14 inches wide. Both types can be broken down to save shipping space.
c. Use of the octagonal tent in the tropics. The same tent also is used in the tropics, though to a very limited extent, because native type thatch huts usually are considered superior. A mosquito netting takes the place of the inner liner in tropical climates.
Section IX. MEDICAL EQUIPMENT
1. GENERAL. Japanese military medical equipment is practical, and civilian medical practices have been considered relatively modern.
2. FIELD EQUIPMENT. a. Drugs. Many of the drugs dispensed have been discarded in European and American medical circles, and some preventatives examined have been found to be without effect. Very extensive use is made of drugs
that have to be injected, and field kits (fig. 407) contain ampoules of a wide variety of sizes and shapes, with no standardization for shipping and packaging. Much use is made of proprietary (patent) medicines, and standard drugs such as quinine, aspirin, and iodine are of course employed. Antimalarials, besides quinine, apparently are being used in increasing quantity. Vaccines and serums are comparable with those in use in other Armies, although there are indications that some of them are not very effective. Vitamin products are used extensively, in the form of powders or tablets (both vitamin B and C) as well as in solutions for injection. Even medical kits contain such vitamin tablets.
b. Instruments. A very great variety of instruments are in use. Most of these appear to be only fair in quality, of nickel-plated carbon steel instead of stainless steel. The case shown in figure 408 is heavy, lined with nickel-plated copper, and equipped with aluminum instrument racks. The tray can be removed with the instruments in it and used as a sterilizer--a very convenient feature. Blood transfusion kits examined are bulky and fragile, usable only with a system of transfusion discarded some years ago by other Armies. No evidence of the use of blood plasma has been found.
Figure 407. First-aid kit and contents.
Figure 408. Field instrument case, showing sterilizer tray.
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