Ki Castle, Mountain fortress in Sōja, Japan
Ki Castle is a mountain fortress in Sōja, Japan, built from wood and stone across forested hills overlooking the surrounding plain. The complex includes reconstructed gates, towers, and defensive lines that follow the natural contours of the terrain.
Emperor Tenji ordered construction in the 7th century after Japanese forces were defeated in Korea, aiming to protect the country from possible attacks. The fortress was part of a network of defensive posts along the coast and inland.
The name is not Japanese for "demon castle": "ki" meant "castle" in the old Baekje language and was later written with the kanji for demon. The site is tied to the Kibitsuhiko-no-mikoto and Ura legend, in which Prince Ura of Kudara ruled from this castle and troubled the villagers until Kibitsuhiko-no-mikoto, linked to Momotarō, defeated him.
The western gate was reconstructed to show how the original 7th-century structure looked and worked. Visitors should wear sturdy shoes as paths cross hilly terrain and climb steep sections in places.
Archaeologists found special paving stones designed to protect the walls from erosion. This technique was unusual for Japanese fortifications of the period and shows the high level of planning that went into construction.
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