When the Boshin War broke out, Sasaki joined the shogunate army participating in the Battle of Toba-Fushimi during which he was fatally wounded and died in Wakayama.
戊辰戦争が勃発すると幕府軍の一員として鳥羽・伏見の戦いに参戦するも重傷を負い、和歌山で死去。