In the Koso Alliance (an alliance between the Takeda clan in Kai Province and the Hojo clan in Sagami Province) in 1571, he was taken by the Takeda clan as a hostage together with Ujitada HOJO.
元亀2年（1571年）の甲相同盟の際には北条氏忠とともに武田氏への人質となっている。