The Ritsuryo system also stipulated that an emperor who abdicated while still alive was to be the Daijo Emperor (or Joko [the Retired Emperor]), which was an original aspect of the Japanese Ritsuryo system and not seen in the Chinese one.
また、皇位を生前譲位した者は太上天皇（上皇ともいう）と規定されていたが、これは中国律令にない独自の地位である。