In the Heian period, a plan was put out for making the Shinno, who was not able to become a Togu (crown prince) due to Emperor Kammu's policy, a Minister for one of the eight central ministries, but later, from a passive viewpoint towards putting political responsibility on a Shinno, it became a custom for a Shinno to take the position of an honorary office such as the Ministry of Central Affairs, Ministry of Military (Treasury code), Ministry of Ceremonial, Danjoin, and Dazai no sochi, where they received only stipends and did not participate in state affairs.
平安時代、桓武天皇の政策により東宮とならなかった親王を八省卿にする方針が打ち出されたが、後に親王に政治責任を負わせることに消極的な立場から中務省、兵部省兵部省(律令制)、式部省、弾正尹、大宰帥といった名誉職に就いて俸禄のみを得て、政務には携わらないという慣習ができた。