Under the Ritsuryo system, it was generally accepted that the status of the Daijo emperor was equal to that of the reigning emperor, although in fact, the Daijo emperor was often ranked higher than the reigning emperor.
律令上、太上天皇を天皇と同等の地位と解釈することが通例とされており、実際には太上天皇が天皇よりも上位とされることも多かった。