History and museums
Usuki Castle (臼杵城, Usuki-jō) is a Japanese castle in Usuki, Ōita Prefecture, Japan. Another name of this castle is Nyūjima Castle (丹生島城, Nyūjima-jō).
This castle was constructed by Ōtomo Sōrin in 1562 on the island Nyū-jima, in Usuki Bay as his head castle. During the 1560s, Sōrin had the largest territory in Kyūshū. However, after defeat at the Battle of Mimikawa in 1578, the power of Sōrin and the Ōtomo clan rapidly declined. In 1586, this castle fell to Shimazu Yoshihiro, a daimyo of Kagoshima, but was rescued by Toyotomi Hideyoshi.