高田藩
Saitō, along with the few remaining men of the Shinsengumi who went with him, fought against the imperial army at Nyorai-dō (a small temple near Aizuwakamatsu Castle), where they were severely outnumbered. It was at the Battle of Nyorai-dō that Saitō was thought to have been killed in action; however, he managed to get back to Aizu lines and joined the Aizu domain's military as a member of the "Suzakutai". After Aizuwakamatsu Castle fell, Saitō and the five surviving members joined a group of former Aizu retainers who traveled southwest to the Takada Domain in Echigo Province, where they were held as prisoners of war. In the records listing the Aizu men detained in Takada, Saitō is on record as Ichinose Denpachi.