Shirakawa (白河天皇, Shirakawa Tennō, July 7, 1053 - July 24, 1129) was the 72nd emperor of Japan, according to the traditional order of succession, and reigned from January 18, 1073 to January 3, 1087.
His personal name was Prince Sadahito (貞仁). While he was not the first emperor to retire to a monastery and still continue to exercise power after his abdication, it was from him that the practice became systematic until the end of the Heian period, and took on the name of insei or withdrawn government.
During his early youth, relations between Sadahito and his father were very cold, but in 1068, when his father ascended the throne, he was given the title of shinnō (imperial prince), becoming imperial prince Sadahito (貞仁親王).
In 1069 he became crown prince, and in 1073, at the age of 19, he became emperor, and his half-brother then took the title of crown prince.
A kampaku regent was established, but when his father died later that year, he tried to rule directly like his father. He tried, like the latter, to regulate the shōen system, working to weaken the influence of the Fujiwara clan sekkan.
In 1085, his half-brother died, and Shirakawa then appointed his own son Taruhito as crown prince. The same day Taruhito became crown prince, Shirakawa abdicated, and Taruhito became emperor Horikawa.
After his abdication, Shirakawa continued to rule as a retired emperor, from the Shirakawa-in (literally, the "White River Temple".
The emperor took his posthumous name from this palace). Although sesshō and kampaku regents continue to be appointed for a long period, power is now in the hands of the retired emperor and no longer in those of the Fujiwara regents.
When Horikawa came of age to rule, Shirakawa did not relinquish power to him and continued to rule from his retirement.
A firm believer in Buddhism, he became a monk in 1096 (upon the death of his daughter) under the name Yūkaku (融観), and continued to rule with the title of hōō (法皇).
After Horikawa's death in 1107, Horikawa's son became Emperor Toba, who in turn abdicated in favor of his own son Sutoku in 1123, forced by the removed emperor. At his death in 1129, Shirakawa reigned as a retired emperor for 41 years and through the reign of three de jure emperors.
Shirakawa was the eldest son of the emperor Go-Sanjō. He had many children, including the future emperor Horikawa. According to one theory, he was also the father of Emperor Sutoku, who according to the official genealogy is the son of Emperor Toba, Shirakawa's grandson.