Aya Castle is a hilltop style Japanese Castle on Mt. Ryuubi in Aya Miyazaki Prefecture on the island of Kyushu. In 1331 Koshiro Yoshito ordered the construction of Aya Castle, which derived its name from the term Koshiro Yoshito referred to himself, Aya. In 1577 the Shimazu clan defeated the Ito clan and gained control of Aya Castle. Niiro Hisatoki was then put in control of Aya Castle by the Shimazu clan. In 1587 Toyotomi Hideyoshi captured Aya Castle. In 1615 most of Aya Castle was destroyed under the shogunal decree of one castle per domain. In 1985 a wooden donjon (tower) was built in a style similar to one that existed at Aya Castle. This tower contains a museum.