Oshima Island
Rock walls and a large lava tube
One of the largest lava tubes in the Goto Islands can be found on Oshima Island, the biggest and southernmost of the three islands that lie to the east of Fukue Island. Located on the unpopulated southern side of the island, the lava tube extends some 130 meters into the earth. The interior is walled with brightly shining pyrite crystals, while countless volcanic stalactites have formed on the ceiling. The various species of animal life found in the lava tube are now being studied by university researchers, who believe that some may be unique to the island. Another geographical feature of Oshima is Mt. Hosogatake, a rounded rise on the island’s western side that is the lowest mountain in Nagasaki Prefecture, at 25 meters.
Volcanic rock is used throughout the Goto Islands to build walls around houses, and Oshima is no different. Here, the walls are made of roughly stacked piles of rounded black rocks, often topped off with piles of smaller rocks, with half-moons of granite set on the top of the walls at entryways. Notable exceptions are the carefully fitted smooth rock walls found near the boat landing; these once surrounded a large official building that later was used as a police station. Today, Oshima Island is home to a population of 50 islanders, a post office, and a Buddhist temple with a statue-lined garden and large graveyard. Accommodations are available on the island.
