During the period of Keiko Emperor (the father of the prince YAMATO Takeru) a karami-bashi, which was built with dugout canoes lined up side by side on the river with wisteria and arrowroot vine twined around them, was constructed and used for crossing the river.
景行天皇(日本武尊の父)の時代に丸木舟を横に何艘も並べ、藤や葛のツタで絡めた搦橋が架けられた。