Kiyoyasu gained control of the whole of northern Mikawa Province after the Saigo clan surrendered following four generations of conflict.

Oda later made secret overtures to the effect that if Kiyoyasu attacked his province he would be on his side, his intention being to oust his elder brother Nobuhide, the head of the clan.

When Kiyoyasu heard of this he was naturally very troubled at the possibility of his base being taken behind his back, and he was rendered more so by another rumour started by someone that his most faithful retainer Abe Sadayoshi was also in league with his uncle.

Abe Sadayoshi was very indignant when he heard this slander, and called his son Yashichi, telling him that it was false, and would be proved so if proper examination was made.

Hearing the noise, Yashichi at once concluded that his father was being arrested and was in danger, and without more Ado rushed out on the spur of the moment without any reflection and cut Kiyoyasu down.