On September 18 of the same year (old calendar), when SERIZAWA became severely drunk during a party held by the Aizu domain in Sumiya and returned to base, KONDO's faction surprise attacked SERIZAWA in his sleep and killed him.
同年9月18日(旧暦)、会津藩の催した角屋での宴会で泥酔して屯所に帰宅した芹沢は、寝込みを近藤勇一派に襲われて絶命した。