The next epoch, called the Initial Period by the American scholar John H. Rowe, and the Lower Formative by the Peruvian archaeologist Luis G. Lumbreras, began with the introduction of pottery. The earliest ceramics have yielded radiocarbon dates of about 1800 bc, although Rowe has suggested that even a date of 2100 bc is plausible. Ceramics from this period have been found on the central coast between Las Haldas, in the Casma-Huarmey region, and Lima. These are considerably later than the earliest pottery finds at Puerto Hormiga on the northern coast of Colombia near Panama (before 3000 bc) and Valdivia in Ecuador (c. 2700 bc). The period ends with the spread of the Chavín cult (also called the Early Horizon; see below).
Lumbreras has stressed agriculture as a more telling indicator: while no single starting date has been cited for this achievement, beans may have been cultivated for centuries if not millennia before the date of the earliest pottery. Bottle gourds and squashes were other cultivated species. Potatoes and other tubers, so important in later times, did not keep well in highland circumstances; but some researchers believe that Andean peoples were reliant on wild tubers and rhizomes 10,000 years ago, although these groups had not yet domesticated them. It has been demonstrated that on the coast virtually all the crops that were important in 1532 (with the notable exception of corn) were already known and in daily use during the Initial Period.
The introduction of pottery at first made little difference to the general pattern of life; cooking continued to be done by roasting on hot stones. On the coast, there was a gradual increase in the consumption of cultivated plants, grown mainly in the lower reaches of the valleys; but the basic reliance on seafood continued. An important innovation was the development, or possibly the introduction, of the heddle loom, but, if it was introduced, its origin is not known. At first it seems only to have been used for making plain-weave cotton cloth. Village life and temple buildings spread over the country, except to the far south, where conditions favoured the continuance of hunting and gathering. Corn spread from the centre over most of the coast, and cassava, or manioc (an edible root), and peanuts (groundnuts) appeared there for the first time, their ultimate source being the Amazonian lowlands.
New ceremonial centres showed considerable diversity. Examples include La Florida, a huge pyramid in Lima that formed the nucleus of a yet-unmapped building complex. The Tank site at Ancón consists of a series of stone-faced platforms on a hill. Las Haldas has a platform and three plazas; two smaller similar sites are also known. The old centres at El Paraíso and Río Seco had been abandoned, but, in the highlands, Kotosh continued to be occupied. Any constructions at Yarinacocha in a wet, stoneless area would have been of wood or other perishable materials.
The variety of the pottery suggests that it was derived from several different sources. In the Lima area, the earliest examples are neckless jars and incurved bowls with thickened rims and rounded bottoms, very uneven in shape. Some later types are pebble polished and the jars thinner. Other later types include bottles with straight spouts, which may have simple incised or applied decoration, and open bowls. Finally, as the period drew to a close, tan-coloured decorated wares, with punctate or red-painted areas outlined by incised lines, as well as orange ware with black stripes, were produced. A type found on the south coast is a small, double-spouted bottle with simple negative-painted decoration, the first appearance of a form long-lived in that area and of a decorative technique that later spread widely over the country.
In the highlands, the earliest pottery at Kotosh consists predominantly of simple bowls with somewhat constricted mouths, and bowls with gently rounded bases meeting the vertical to outsloping concave walls at a sharp angle. There are rare double-spout-and-bridge bottles, closed vessels with two tubular spouts connected by a solid bridge. The ware is mainly dark gray, black, or dark brown to sombre red, and it may have a red slip. The decoration—which was either applied to a broad zone covering most of the walls or, on the neckless jars, formed a ring around the mouth—consists of linear incision, hatching, stamped circles, punctation, or excision. Postfired painting in red, yellow, and white frequently covers excised, hatched, and stamped areas. Despite the fact that Kotosh was on the eastern side of the Andean watershed, its pottery had little in common with that of Yarinacocha, save some similar decorations and the double-spout-and-bridge bottle.
The first known pottery of Yarinacocha is far from primitive. It consists mainly of bowls, mostly with complex outlines. Large open bowls with a broad labial flange, concave sides, and in some cases a second flange where side meets base, could have been cooking pots. Small bowls with inward-sloping sides meeting the rounded base at a sharp angle could have served for drinking; and a shallow bowl, with rounded base meeting the low, slightly outsloping concave sides at a lesser angle, may have been a plate for solid food. There are shards from large urns that may have served for brewing cassava beer. Decoration of finely hatched or cross-hatched geometrical areas, outlined by broad incised lines, occurs on most vessels, and one has a similarly executed feline face. In spite of severe weathering, postfired red paint, later so characteristic of the south coast, is found on some vessels.