In 1051 Yoritoki led an army of Emishi into northern Miyagi and defeated a government army at Onikiribe that had been sent to stop the raids. This event triggered the Former Nine Years' War (Zenkunen War).
Yoritoki commanded an Emishi contingent that invaded northern Miyagi in 1051, where they triumphed over a government army stationed at Onikiribe to halt the raids. This victory sparked the Former Nine Years' War (Zenkunen War).