National Treasures & Important Cultural Properties
of National Institutes for Cultural Heritage, Japan

There are two types of ancient Japanese stirrups: Wa-abumi and Tsubo-abumi. Tsubo-abumi have a pot-shaped cover for the toes and emerged after Wa-abumi (a stirrup in the form of loop). Metal Tsubo-abumi are rather new among such stirrups. Among the Imperial Bequest to Horyu-ji Temple, one pair and one half of a pair of Tsubo-abumi can be seen. They are made of iron and the cover and the frame metal are produced differently. The cover is fixed on the frame with iron rivets. They seem to have no sole. There is a possibility that the entire surface of the Tsubo-abumi was lacquered. There is a similar one among the Treasures of the Shosoin Imperial Repository in Nara, but this one seems to have been made a little earlier than that. 　
The cordiform metal fittings (gyoyo) with a gilded bronze buckle (kako) are also preserved as an accessory. As there are rivets left, there is a possibility that leather lined the back. There is also a possibility that the stirrups were part of a set together with a harness.