The unique stirrups used by the samurai were known as Abumi. The earlier versions (pre-Nara period) had only a toe cup for support, while the Nara and Heian periods featured an elongated toe to heel foot-plate for greater support. Usually made of steel, abumi are often decorated with inlay and or lacquer.
The protruding front was known as the Hatomune, or pigeon breast, and the outer areas covering the front of the foot was the Emi. The upright post was known as the Monsukashi, the buckle at the top was the kako, and the spike is called the sasuga. The main plate where the feet stand is called the Shita, while the outer rim edges are called the Yanagiba.
The open sides are supposed to prevent the riders’ foot from catching in the stirrup and being dragged if thrown. This design remained in use until western saddles were introduced during the Meiji period.