Mt. Joyama (Kaneda Castle Ruins)

These ancient castle ruins are located in Kurose, Mitsushima-cho, Tsushima City. After the Battle of Hakusukinoe in 663 when Baekje and Japan fought against the allied forces of the Tang and Silla, Kaneda Castle was built to protect against further attacks by the Tang and Silla, and soldiers monitored the border. In addition, for approximately 1,200 years since, a fortress had been placed there by the former army even before the Russo-Japanese War. A valuable historical site with ancient and modern fortress ruins, it is a nationally-designated special historic site.