And on March 6, Nobukatsu deliberately killed his important vassals such as Shigetaka OKADA and Yoshifuyu TSUGAWA by a nominal reason that they held secret communication with Hideyoshi, which was virtually a declaration of war against Hideyoshi.
そして3月6日、信雄は秀吉に内通したとして、秀吉との戦いを懸命に諫めていた重臣の浅井長時・岡田重孝・津川義冬らを謀殺し、秀吉に事実上の宣戦布告をした。