The influential obtained licenses from Daijokan, Minbusho (Ministry of Popular Affairs) or Kokuga to prevent Kokuga from confiscating their shoen, (the former was called Kanshofu sho: a shoen enjoying immunity from taxation by virtue of having official documents from both the Council of State and the Ministry of Popular Affairs, and the latter was called Kokumen sho: a shoen allowed exemption from so or other tribute in bempo or binho system).
権門層は、荘園を国衙に収公されないよう太政官、民部省や国衙の免許を獲得し、前者を官省符荘といい後者を国免荘という。