It is said that Banshu in the bakufu originally derives from the fact that in the time of MINAMOTO no Yoritomo and the Kamakura bakufu, he arranged for gokenins (immediate vassals of the shogunate) with skill in bow and arrow to stay close to him night and day.
幕府の番衆の元は鎌倉幕府の源頼朝時代に弓矢に優れた側近の御家人を日夜身辺に置いたことに由来するとされる。