When Emperor Tenchi died, he pledged together with Akae Soga and others to support Prince Otomo (later Emperor Kobun). Then Prince Oama (later Emperor Temmu) rose in arms against Prince Otomo. Hatayasu and Prince Yamabe took up a position on the Inukami River to attack Prince Oama. Prince Yamabe, however, wanted to side with Prince Oama but was killed by Hatayasu. The incident plunged his army into uncontrollable confusion and Hatayasu killed himself.