Other than conflicts with Katsuyori, the reason for the betrayal was said that the coup incident by Yoshinobu TAKEDA played a role (his brother Nobukuni took sides with Yoshinobu, leading to suicide), or that his wife Kenshoin suggested to her husband that her real son Nobuharu ANAYAMA (Katsuchiyo) was more suitable as the head of the Takeda family (Nobuharu was three-quarters Takeda clan blood) rather than Katsuyori who was from a line of the Suwa clan--but all such theories lack conclusive evidence.
裏切りの原因については、勝頼との対立の他に、かつての武田義信によるクーデター事件が関係しているとも（弟信邦は義信側に味方したことにより自害）、妻の見性院が諏訪氏の血を引く勝頼よりも、自らが生んだ穴山信治（勝千代）の方が武田家当主に相応しい（信治は武田氏の血を3/4継いでいる）と夫に勧めたためだとも言われるが、いずれにせよ確証はない。