石突(いしづき)ishizuki
Ishizuki
A spike set at the end of a pole so it can be set upright into the ground. In Japan weapons with long handles, like spears, were equipped with ishizuki on their but ends so that they could be stood vertically in readiness for grabbing them, particularly when a warrior was already mounted on a horse. In addition, the pointed iron end fixtures could be used as an alternative method of stabbing.
72nd Annual Exhibition of Shōsō-in Treasures, 2020