According to the "Koyo Gunkan" (a record of the military exploits of the Takeda family), the origins of the confrontation with Shingen lay in the Fourth Battle of Kawanakajima and Yoshinobu's disapproval of his paternal younger brother, Katsuyori SUWA (Katsuyori TAKEDA) becoming the lord of Takato-jo Castle.
なお、『甲陽軍鑑』に拠れば、信玄との対立の原因は、第4回川中島の戦いの顛末や、異母弟の諏訪勝頼（武田勝頼）が高遠城主となったことに対する不満にあるという。