Enkōin was a woman who lived during the Sengoku period.
Enkōin was born as the daughter of Takeda Yoshinobu, the eldest son and designated heir of Takeda Shingen (the nineteenth head of the Kai-Takeda and sengoku daimyō of Kai Province) and his formal wife, Reishōin, the daughter of Imagawa Yoshimoto (the eleventh head of the Imagawa and sengoku daimyō of Suruga Province).
After Yoshimoto prevailed in a succession struggle known as the Hanakura Conflict in 1536, the Imagawa and Takeda clans reconciled. On 12/7 of Tenbun 19 (1550), Yoshinobu attended his coming-of-age ceremony. On 11/27 of Tenbun 21 (1552), Yoshinobu, as the age of fifteen, wed Reishōin as his formal wife. This political marriage sealed the alliance between the Takeda and Imagawa. Thereafter, in the first month of 1553, Shingen’s daughter, Kōbai-in, wed Hōjō Ujimasa, the eldest son of Hōjō Ujiyasu, the third head of the Gohōjō clan and sengoku daimyō of Sagami Province. In the seventh month of 1554, Ujiyasu’s daughter, Hayakawa-dono, wed Yoshimoto’s eldest son, Imagawa Ujizane (Reishōin’s older brother). As a result, the marriage between Reishōin and Yoshinobu served as a link in the three-party alliance between the Takeda, the Imagawa, and the Hōjō.
In 1560, after Imagawa Yoshimoto was killed by Oda forces at the Battle of Okehazama, Takeda Shingen began planning for an offensive to capture the territory of the Imagawa. Meanwhile, based on a desire to preserve the alliance with the Imagawa, Yoshinobu secretly formed a faction within the Takeda family opposed to his father in an event known as the Yoshinobu Incident. Informants notified Shingen of the plot, whereupon Yoshinobu was incarcerated in the Tōkō Temple and his band of retainers purged. It is surmised the Reishōin was forced to separate from Yoshinobu at this time, but she remained in Kōfu.
On 10/19 of Eiroku 10 (1567), Yoshinobu either took his own life or died of illness at the Tōkō Temple. In the eleventh month, Reishōin, upon demand of her older brother, Imagawa Ujizane, was returned to the Imagawa family in Suruga. Accompanied by Enkōin, after returning to Suruga, Reishōin entered the priesthood. Enkōis is surmised to have lived until the decimation of the Imagawa in 1568, but the details of Enkōin’s life thereafter are unknown.
According to genealogical records, Yoshinobu and Reishōin had one daughter, Enkōin. A historical account of Kai from the late Edo period notes the couple had two daughters.