Chūkyō (1218-1234), was the 85th Emperor of Japan, according to the official chronology. At the age of 4 years old, Chūkyō was enthroned as Emperor of Japan for only a few short months in 1221, when his grandfather, retired emperor Go-Toba, had his father Emperor Juntoku abdicate in his favor in preparation for the Go-Toba's attempt to overthrow the Hojo Shogunate (aka the Jokyu War).
When Go-Toba's side lost the brief war, the Shogunate made Chūkyō abdicate in favor of his first cousin once removed, Emperor Go-Horikawa. Go-Toba and Juntoku were both exiled to remote islands, and the now suddenly father-less and grandfather-less Chūkyō was hustled back to the house of his mother's family, the Kujō (a branch line of the Fujiwara), where he lived in seclusion until his untimely death from illness at the age of only 17, in 1234.
Because Chūkyō's reign was so short, and happened amidst the chaos of the Jokyu war, and because the Hojo Shogunate and their stooge Go-Horikawa were disinclined to legitimate the machinations of Chūkyō's lately vanquished and banished father and grandfather, Chūkyō was actually not officially recognized as one of the emperors of Japan for many centuries after his death.
Since for most of Japanese history emperors were not given reign names until after their deaths, Chūkyō was never given a name other than his original given name (which was "Kanenari"). This meant that for many centuries, Japanese historians had to refer to him in their chronologies by one of several nicknames, such as the "Kujō Dethroned Emperor" (Kujō Haitei, 九条廃帝) after his mother's family name, the "Half-Emperor" (半帝), or the "Later Dethroned Emperor" (Go-Haitei, 後廃帝), a reference to an earlier unrecognized emperor, Junnin, who was the original "Dethroned Emperor."
Indeed it was not until 1870, when the newly organized Meiji government was trying to get kinks in the national history ironed out, that the Meiji Emperor finally rehabilitated Chūkyō as an official emperor, and gave him his reign name of "Chūkyō."
<< Juntoku - Emperors of Japan - Go-Horikawa >>