During their heydays, the Japanese castles were surrounded by dozens of turrets, called yagura. Yagura were multirole structures, being used as defensive fortifications, observations towers, and even as warehouses.
Due to their complex usage, they were usually named according to their role, e.g. Yari Yagura was the turret where the spears (yari) were stored, Teppō Yagura was the turret storing the arquebuses (teppō), Hata Yagura was a store for flags (hata), Shio Yagura was a salt (shio) warehouse, and Ido Yagura was housing a well (ido in Japanese).
Yesterday’s Japan Photo: