Under Hakodate Government (Ezo Republic), he became an immediate subordinate of Toshizo HIJIKATA who took office as 陸軍奉行並 (the corresponding post of an army commissioner), and then, he served as Hijikata's assistant from the battle at Fatamataguchi to the all-out assault of Hakodate.
箱館政権(蝦夷共和国)下では、陸軍奉行並に就任した土方歳三直属の部下となり、二股口の戦いから、箱館総攻撃に至るまで土方の補佐役を務めた。