According to Shinto mythology, the 12-meter-long boulder at Iwafune Shrine is believed to be a fragment of the celestial rock boat used by the deity Nigihayahi-no-Mikoto to descend from the heavens to earth. The name "Iwafune" literally translates to "rock boat," directly referencing this ancient legend. This massive stone, weighing approximately 12 tons, has been worshipped for over 1,200 years as a sacred object representing the divine connection between heaven and earth.