However, after the middle of the Heian Period when the procedures of the ritsuryo system (a system of centralized government based on the ritsuryo code) became relaxed, the case that an appointment was made by the issued appointment letter appeared.
だが、平安時代中期以後に律令制の手続が弛緩すると、補任状の発給によって補任とする例が現れる。