S P O T ／ SPOT-222

Onigashima Great Cave (Megijima Island)

鬼ヶ島大洞窟おにがしまだいどうくつ

The Onigashima Great Cave is a man-made cavern roughly 400 meters long and 4,000 square meters in area, carved into the slopes beneath Mount Washigamine on Megijima Island in the Seto Inland Sea, about 4 km off the coast of Takamatsu, Kagawa Prefecture. The cave was surveyed in 1914 by Sentaro Hashimoto, a local historian and elementary school principal from nearby Kinashi, and in 1931 he publicly linked it to the legend of Momotaro, framing Megijima as the mythical Onigashima ("Ogres' Island"). The cave's true origin remains debated: hypotheses include a Yayoi-period dwelling, a medieval fortress, an Edo-to-Meiji quarry for Teshima stone, and a hideout used by Inland Sea pirates. Inside, chambers named after Momotaro's tale, the great hall, living room, women's prison, and guards' quarters, hold a steady year-round temperature around 15 degrees Celsius. Today the site is operated by the Onigashima Tourism Association and doubles as a Setouchi Triennale venue, hosting Goro Murayama's evolving wall drawing and the Oninoko Roof Tile Project, where folklore meets contemporary art. A 20-minute ferry ride from Takamatsu Port makes it one of Kagawa's most accessible folkloric landscapes.