Lit. "Korean type mountain castle." A general term for castle structures in Japan that resemble those in ancient Korea. Representative examples include: the so-called sacred stones *kōgo-ishi 神篭石 in northern Kyūshū 九州, western Honshū 本州, and Shikoku 四国; the mountain castle at Kōrasan 高良山 in Fukuoka Prefecture; the ruined mountain castle Kiyama-jō 城山城 in Kagawa Prefecture; Ōno-jō 大野城 in Fukuoka Prefecture, which was constructed for the defense of Dazaifu 大宰府 (665); Kii-jō 基肄城 in Saga Prefecture; and Ido-jō 怡土城 in Fukuoka Prefecture, completed in 768. Ōno-jō and Kii-jō both are to have been constructed with the advice of Korean (Baekje, Jp: Kudara 百済) experts because both are similar to sites found in various parts of the Korean peninsula. All these fortifications are characterized by earthen embankments which served as walls and stone work employed at strategic points, such as entrances. In the case of Ōno-jō, the embankment extended for a length exceeding nine kilometers. It measured 8 m wide at its base and 2 m high. In ancient Korea, castles functioned as secure shelter for troops and civilians to escape to in time of emergency. In Japan, Korean type castles seem to have continued this tradition because the remains of storehouses have been located within their walls.