Since the feudal retainers of the Aizu clan could not handle all the work by themselves, Shinsengumi (a group who guarded Kyoto during the end of Tokugawa Shogunate) was stationed under their control as being in custody of shugoshoku, and to attend to maintenance of security.
会津藩士のみでは手が回りきらなかったため、守護職御預かりとして新選組をその支配下に置き治安の維持に当たらせた。