Jōkei-in (1519-1550) was the eldest daughter of Takeda Nobutora, the sengoku daimyō of Kai Province and formal wife of Imagawa Yoshimoto. Yoshimoto was the military governor, sengoku daimyō, and eleventh head of the Imagawa clan of Suruga and Tōtōmi provinces. Her mother was Ōi-no-kata. Jōkei-in was the elder sister of Takeda Shingen, Takeda Nobushige, and Takeda Nobukado.
Early in 1537, she wed Yoshimoto at the age of eighteen. Yoshimoto had just prevailed the prior year in a succession struggle known as the Hanakura Conflict (Hanakura no ran). His marriage to Jōkei-in reinforced the political alliance with the Takeda of Kai but invited the scorn of Hōjō Ujitsuna of Sagami Province. A longtime rival of the Takeda clan, Ujitsuna was the second lord of the Gohōjō clan with the status of a sengoku daimyō. Ujitsuna responded by invading Suruga, burning the area near Okitsu, marking the start of the Katō Conflict (Katō no ran). Takeda Nobutora and his cavalry advanced to Subashiri in support of the Imagawa, but the Gohōjō occupied the area to the east of the Fuji River. Clashes between the Imagawa and Gohōjō ensued from 1537 to 1545 in the contested area between the Fuji River and the Kise River near the borders of Kai, Suruga, and Sagami provinces.
In 1538, Jōkei-in gave birth to Imagawa Ujizane as the eldest son of Yoshimoto. Thereafter, she bore daughters named Reishōin and Kōfukuin. In the summer of 1541, Takeda Nobutora visited Suruga to meet his daughter and her husband, but his eldest son, Harunobu, prohibited his return so he remained in Suruga.
Jōkei-in died in the summer of 1550 at the age of thirty-two. To maintain the alliance between the Takeda and the Imagawa, late in 1552, her daughter, Reishōin, married Nobutora’s nephew, Takeda Yoshinobu. This was a marriage between cousins. Meanwhile, the daughter of Takeda Shingen, Ōbai-in (Jōkei-in’s niece), wed Hōjō Ujimasa, and the daughter of Hōjō Ujiyasu, Hayakawa-dono, wed Imagawa Ujizane in connection with the three-way alliance between the Takeda, the Gohōjō, and the Imagawa known as the kōsōsun-sangoku-dōmei.