In the past, Ganryu-jima had been called Funa-shima; a master of the sword, Musashi MIYAMOTO and Ganryu SASAKI had an argument over the art of warfare, they carried out a fight of art of sword at the island, and Ganryu was struck to the death by Miyamoto.
岩龍島は昔舟島と呼ばれていたが、宮本武蔵という刀術者と佐々木岩龍が武芸論争をし、この島で刀術の試合をし、岩龍は宮本に打ち殺された。