However, Michito did not let Ushinosuke, the son of late older brother Toshisada, take over as the head of the family even when he turned 15 years old and Michito attempted to let his own son Norimichi INABA take over instead; therefore, Ushinosuke began to feel disaffected.
しかし、長兄・利貞の遺児である牛之助が15歳に成長しても家督を譲ろうとせず、実子の稲葉紀通に譲ろうとしたため、牛之助が不満を抱く。