|Vietnamese alphabet||Thái thượng hoàng|
Retired Emperor, Grand Emperor, or Emperor Emeritus is a title occasionally used by the monarchical regimes in the Sinosphere for former emperors who had (at least in name) abdicated voluntarily to another member of the same clan, usually their sons. This title appeared in the history of China, Japan, Korea, and Vietnam. Although technically no longer the reigning sovereign, there were instances like the Qianlong Emperor of the Qing dynasty of China or several emperors of the Trần dynasty of Vietnam, where the emperor continued to exert considerable if not more power than the reigning emperor.
Main article: Taishang Huang
The title is named in Chinese as Taishang Huang (Chinese: 太上皇; pinyin: tàishàng huáng; Wade–Giles: T'ai4-shang4 Huang2). The title originated, however, from Liu Bang (Emperor Gao of Han)'s father Liu Taigong, who was honored as such after Liu Bang declared himself emperor in 202, even though Liu Taigong was never emperor himself.
Main article: Daijō Tennō
In Japan the title was Daijō-tennō (kanji: 太上天皇; Hepburn: daijō-tennō), or just Jōkō (kanji: 上皇; Hepburn: jōkō). In Japan, there was a political system called Cloistered rule, in which Jōkō exerted power and influence from behind the scenes even after retirement.
Main article: Taesangwang
In Korean the title was Sang-hwang (Hangul: 상황; Hanja: 上皇), or sometimes even Taesang-hwang (hangul: 태상황; hanja: 太上皇). After 1897, when the Joseon Dynasty became the dynasty of the Korean Empire, only two emperors were still to ascend to the throne. One was Emperor Gojong, who was forced to abdicate by the Japanese in 1907. However, he was given the title Tae-hwangje (Hangul: 태황제; Hanja: 太皇帝). also another emperor was Emperor Sunjong. but after the Japan-Korea Annexation Treaty of 1910, the Imperial Household was demoted by the Empire of Japan.
In Vietnam the title was Thái thượng hoàng (quoc ngu: Thái thượng hoàng; chu nom: 太上皇), or just Thuong hoang (quoc ngu: Thượng hoàng; chu nom: 上皇).