During the formation of the Shugo-ryogoku system at the time of the wars between the Northern and Southern Courts, the Muromachi bakufu and Shugo daimyo, who controlled lands, took over the authority to impose or exempt public duties or taxes from the Imperial Court and provincial officials.
南北朝の戦乱の中で守護領国制が形成されていく中で室町幕府及び在地を支配する守護大名が朝廷・国衙に代わって国役の賦課・免除の権限を掌握するようになる。