Since Koryo (Imperial demesne, or Kokugaryo) under the Ritsuryo system persistently continued even after the spread of the manorial system, there was room for Joko to use considerable power until the establishment of the Kamakura Bakufu.
荘園制の普及にもかかわらず律令体制下の公領（国衙領）がなお根強く残されていたことから、鎌倉幕府の成立前後までは上皇がかなりの権力を振るう余地はあった。