The Emperor of Orii

…Other examples of people who received the honorific title of Retired Emperor without ascending to the throne include Prince Morisada (Gotakakurain), the father of Emperor Go-Horikawa, and Prince Sadanari (Go-Sukōin), the father of Emperor Go-Hanazono. Examples of people who were posthumously awarded the honorific title include Prince Masahito (Yōkōin), the father of Emperor Go-Yōzei, and Prince Norihito (Emperor Keikō), the father of Emperor Kokaku. In addition to the above abbreviations, there are also Japanese-style titles for the retired emperor, such as "Ori no Mikado," "Motono no Ue," and "Munashiki Fune," all of which are titles that indicate abdication, with "Munashiki Fune" being the Japanese reading of "Utsuro Fune," which originates from China. However, the most widely used titles were in, Sen'in, and Sen'dō, which were derived from the name for the retired emperor's palace. When there were multiple retired emperors in existence, they were distinguished by calling them Ichi'in, Hon'in, Chu'in, and Shin'in. …

*Some of the terminology that refers to "Ori no Mikado" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…そのほか，皇位につかずして太上天皇の尊号をうけた例に，後堀河天皇の父守貞親王(後高倉院)と後花園天皇の父貞成親王(後崇光院)があり，没後に尊号を追贈された例に，後陽成天皇の父誠仁親王(陽光院)と光格天皇の父典仁親王(慶光天皇)がある。太上天皇の異称には，上記の略称のほか，〈おりゐのみかど〉〈もとのうへ〉〈むなしきふね〉などの和風のものもあり，みな譲位の意による称で，〈むなしきふね〉は中国に出典のある〈虚舟〉の和訓である。しかしもっとも広く行われた異称は，上皇の御所を指す呼称から転じた院，仙院，仙洞などで，上皇が複数現存した場合は，一院または本院，中院，新院とよんで区別した。…

※「おりゐのみかど」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報