Onigashima Cave

Onigashima Cave is located on Megijima Island in the Seto Inland Sea, approximately 20 minutes by ferry from Takamatsu Port in Kagawa Prefecture, Japan. The cave derives its name from the legendary island of Onigashima, meaning "Demon Island," which appears in the famous Japanese folktale of Momotaro, the Peach Boy who defeated ogres with the help of animal companions.

The cave system stretches approximately 400 meters into the island's rocky interior and was originally created through natural erosion processes, though parts were later expanded for defensive purposes. Historical records suggest the caves were used as fortifications during Japan's Sengoku period in the 16th century, when local warlords utilized the natural formations for military advantage. The association with the Momotaro legend has made this site a significant cultural landmark, connecting visitors to one of Japan's most beloved folk stories.

Inside the cave, visitors encounter a series of chambers decorated with colorful demon statues and displays that recreate scenes from the Momotaro tale. The atmospheric lighting enhances the mythological ambiance, while the cool interior provides respite during summer months. The walk through the cave system takes approximately 30 to 40 minutes, following a well-maintained pathway that includes some stairs and uneven surfaces. The cave exit opens to a scenic observation point offering panoramic views of the Seto Inland Sea and neighboring islands.

Megijima Island can be reached by regular ferry service from Takamatsu Port, with boats departing multiple times daily and the journey costing around ¥370 one way. From the ferry terminal, Onigashima Cave is accessible via a 15-minute walk uphill or by rental bicycle available near the port. Admission to the cave costs ¥500 for adults and ¥250 for children. The island also features the Setouchi Triennale art festival every three years, during which contemporary art installations complement the historical cave attraction.