Sadayo met with three of the most powerful families on Kyūshū to gain their support in the attack, those families being the Shimazu, the Ōtomo and the Shōni. Things seemed to be going well until Sadayo suspected the head of the Shoni family of treachery and had him killed at a drinking party. This outraged the Shimazu clan, who had originally been the ones to convince the Shōni to throw their lot in with Sadayo, and they returned to their province of Satsuma to raise a force against Sadayo. This gave Prince Kanenaga time to regroup, and he forced Sadayo back North, prompting Sadayo to request assistance from the Bakufu.