Unlike the existing constitution, the title imperial prince/princess was given to those down to the great-grandchildren of the emperor, and great-great-grandchildren and later generations were given the title prince or princess (Article 31 of the former Imperial House Act).
現行憲法下と違い、四世孫（皇親族）までが親王・内親王とされ、五世孫以下が王・女王とされていた（旧皇室典範31条）。