After Takeda clan ruined, Kai Province was conquered by Ieyasu TOKUGAWA by way of the disorder of Honnoji Incident, at the time, the old retainers of the Takeda Family were alloted to Naomasa II, counted one of the Tokugawa-shitenno (four generals serving Tokugawa Ieyasu).
武田氏滅亡後、本能寺の変の混乱を経て甲斐国は徳川家康によって平定されるが、その折に武田家の旧臣達を配属されたのが徳川四天王にも数えられる井伊直政である。