The west small keep is 15.2 metres tall, excluding the stone wall, with three stories above ground and two below. Located on the west side of the main tower, it is surrounded by six gates and five "masugata" open spaces used to attack enemy forces from above. Shigehiro Kudo, curator of the municipal Himeji Center for Research into Castles and Fortifications, points out, "It overlooks the only route to the castle's main keep, and can be said to be the last defensive facility to protect the main tower from enemies attempting to invade." The interior of the west keep is largely undecorated, and on the walls are tool hangers that are thought to have been used to hang match cords and coats, among other items, and "sama" narrow windows where the muzzles of matchlocks were pointed toward the outside. Looking down from the window, the shape of the "masugata" open spaces can be seen.