Ishikari River
According to the "Nihon Shoki", the Mishihase first arrived at Sado Island during the reign of Emperor Kinmei. In 660, Japanese General Abe no Hirafu defeated the Mishihase in "Watarishima" at the request of the native inhabitants. During the Edo period, Arai Hakuseki proposed that Watarishima was Ezo, which was later renamed Hokkaidō. The battle place was recorded as the mouth of a large river, which is proposed to be Ishikari River.