Reigning Emperor (Japanese: 今上天皇 Hepburn: Kinjō Tennō) or Majesty (陛下 Heika), according to protocol, is the honorific title used in Japan to refer to the current Emperor of Japan instead of using their personal name (e.g. Hirohito), as is done in the West. The only context where the personal name is used is when referring to their time before taking the throne (e.g. Prince Hirohito 裕仁親王 Hirohito shinnō).
Under the modern system, the posthumous name (諡号 shigō, colloquially gō) of the emperor will always match the era name or regnal year name (元号 gengō). However, this "one generation one title" (一世一元 issei ichigen) system was only implemented in the modern age of the Meiji Restoration. In the past, the emperor's name never matched the era name, and the change of the era name (改元 kaigen) could occur any number of times. Additionally, some emperors had two gō titles, when reoccupying the throne in a process called chōso (重祚). One example of this was Empress Kōgyoku, who later mounted the throne as Empress Saimei.
Attaching the title "Emperor" and his Japanese era name has formed a posthumous name, from "Emperor Meiji" to "Emperor Taishō" and "Emperor Shōwa", so doing it to refer to still living Emperor Emeritus Akihito and the Reigning Emperor Naruhito is a faux pas.
- Erskine 1933, quote: "In Japan, the personal name of the Emperor is never used by the people. He is always spoken of as the Heika or the Kinjo no Heika while living, and after his death is spoken of as the "Meiji Tenno" or " Taisho Tenno"
- Tanaka 2006
- "上皇さまを「平成天皇」と呼ばない理由" [The reason why the Emperor Emeritus is not called "Emperor Heisei"]. BuzzFeed (in Japanese). 2019-05-03. Retrieved 2019-05-03.
- Izawa, Motohiko (井沢元彦) (2011), 井沢元彦の学校では教えてくれない日本史の授業 (Izawa Motohiko no gakko dewa oshiete kurenai Nihonshi no jugyo) (preview), PHP Kenkyujo, p. 180, ISBN 9784569795232
- Erskine, William Hugh (1933), Japanese Festival and Calendar Lore (snippet), Kyo Bun-kwan, p. 67
- Tanaka, Stefan (2006), New Times in Modern Japan (preview), Princeton University Press, p. 11, ISBN 9780691128016