In the Mongolian invasion attempts against Japan, at the Bunei War (the first attempt), Japanese warriors experienced that the traditional Japanese samurai fighting style, one-on-one battle, did not work against Mongolian army, which attacked as a group, so that at the Koan War (the second attempt), under the regent Tokimune HOJO, he dispatched Tokuso's vassals, Miuchibito, to the battle fields and they commanded the army predominated by Gokenin (direct shogunal retainers).
元寇の際、文永の役において、一騎打ちを主な戦法とする日本軍が元(王朝)軍の集団戦法に苦戦した経験から、弘安の役においては、作戦指令が執権北条時宗の名で出され、得宗被官たる御内人が戦場に派遣されて御家人を主体とする軍の指揮にあたった。