Yoshikane, who had been Kazusa no suke (Assistant Governor of Kazusa Province) at the time and persuaded Sadamori to support him, deployed a large force before joining his brother Yoshimasa and Sadamori in Mimori in June 935.
現任の上総介だった良兼は貞盛を説得して味方に引き入れ、承平6年（935年）6月大軍を動員して館を出発、水守で良正、貞盛と合流した。