In the process of establishing the kokuga forces system, shodaibu (aristocrat lower than Kugyo) (military aristocrat) or samurai officials who specialized in military arts appeared and some of the military aristocrats went to various provinces, especially those of eastern Japan, in order to serve as kokushi.
国衙軍制成立の過程で武芸、すなわち軍事を専門とする諸大夫身分の貴族（軍事貴族）や侍身分の官人層が出現し、これらの層の上層身分たる軍事貴族層では、特に東国を中心として、自ら国司として現地赴任する者も現れた。