The military service imposed on the immediate vassals of the shogunate in the Kamakura period included the guard duty in Kyoto and Kamakura, to search and capture and the like, and in wartime, they would summarily rush to the place, 'Iza Kamakura' (To Kamakura with haste).
鎌倉期の幕府御家人に課せられた軍役は、大番役や追捕などであり、戦時には「いざ鎌倉」とはせ参じた。