It used to be one of the islands at Tomonoura, but today the island is connected to the main island which was made so by land reclamation at the time of constructing the Tomo-jo Castle in Keicho era (1596 to 1615).
-かつては鞆の浦に浮かぶ島のひとつだったが、慶長時代の鞆城築城時に埋め立てられ陸続きとなっている。