The “Tamon Yagura” of Osaka Castle is one of the most important defensive facilities in the castle, and has distinguished itself along with the castle's history. The name “Tamon Yagura” comes from the name of Tamon-ten, a Buddhist guardian deity, because of its row-house style of construction. This turret was built at a strategic point in Osaka Castle, where it could be seen from inside and outside the castle. The Tamon turret of Osaka Castle is said to have existed since the time of the first Osaka Castle built by Toyotomi Hideyoshi, but the one seen today was rebuilt in the Edo period. After the fall of the Toyotomi clan, Osaka Castle was rebuilt by the Tokugawa Shogunate following the Battle of Osaka, at which time the Tamon turret was also rebuilt as an important structure to strengthen the defensive functions. Architecturally, it was generally built long and narrow along the castle moat, with a multi-story structure, and was equipped with a narrow space (sama) for firing flintlock rifles and arrows, as well as other defensive devices. These designs prevented enemies from entering the castle and served as a defensive stronghold for the soldiers inside.