Haramaki is a form of Japanese armor invented in the 13th century.
Haramaki is constructed similarly to oyoroi and domaru. Small metal (preferably iron) and leather scales are laced together onto plates, and lacquered. To reduce cost, these plates were typically larger than those used in oyoroi and domaru. These plates are then laced together to form the armor.
Domaru and haramaki are very similar in form and can be difficult to distinguish. The most obvious difference is that domaru is fastened under the right arm, while haramaki is fastened in the middle of the back. This leaves the back more vulnerable. Theoretically, this isn't a problem, since the only time your back is towards your opponent is when you're running away. Many pieces do have a "coward plate" to protect the back.