In September of the same year, he formed the Mitate party with Ichinoshin ODA and Yajiro SHINAGAWA, fighting hard in the Shimonoseki War as Assitant Deputy General, however, the Choshu Domain was defeated.
同年8月、大田市之進、品川弥二郎らと御楯隊を創設し、軍監となって下関戦争で奮戦するも長州藩は敗北した。