The most famous old tale among the Japanese is most likely Momotaro (桃太郎 in Japanese). The summary of the story is as follows : “A boy, who was born from a peach and came from an upstream, was named Momotaro. When he grows up, he takes some Kibidango (sweet dumpling made with mocha flour and millet flour, 吉備団子 in Japanese), and sets off on a journey to subjugate the Oni (devils, 鬼 in Japanese). On the way, Momotaro finds a dog, a monkey and a Japanese pheasant, and they become his followers. The 4 arrive at Onigashima, (the island of Oni, 鬼が島 in Japanese) where the Onis are waiting for them. After a hard battle, the 4 beat the Onis, and take back the treasures that the Onis stole from the people, and Momotaro brings peace to the world.”
Onigashima, officially called “Megishima” (女木島 in Japanese), is located in the sea of Japan (瀬戸内海 in Japanese) and belongs to Kagawa Prefecture, Shikoku District. It is said that the tale of Momotaro originated in Kagawa prefecture.
In 1914, the cavern was found by Sentaro Hashimoto, a local history researcher, and started to be exhibited as “Onigashima” cavern in 1931. This cavern is thought to have been made in around 100 B.C. and is also similar to fortress caverns of Ancient China. Its length is about 400 meters long, and the all-around size is about 4000㎡.
You can take a ferry from the Port of Takamatsu to Megishima directly, the trip takes about 20 minutes.
From the Port of Megishima, you can either take a bus to the cavern (it takes around 10 minutes) or walk there (around 30 minutes).