In 1184, he attacked MINAMOTO no Yoshitsune's army from ambush in Mt. Mikusa in Harima Province with his brothers: Sukemori, Arimori and Tadafusa; but they were defeated in the enemy's night attack (the Battle of Mikusayama [Mt. Mikusa]).
寿永3年（1184年）、播磨国三草山にて、兄弟の資盛、有盛、忠房とともに源義経軍を迎撃するも、夜襲を受けて敗れる（三草山の戦い）。