Jôkei-In was Takeda Nobutora's oldest daughter. She was married to Imagawa Yoshimoto on the second day of the sixth month of 1537 to cement relations between the two clans, and was the mother of Imagawa Ujizane and two daughters. This marriage would result in a Hôjô invasion which reached all the way to Okitsu, an advance stopped with Nobutora's assistance (see Kato no Ran).
After her death, relations soured between the Takeda and Imagawa, and as a result, in 1552, Takeda Yoshinobu was married to one of her daughters by Yoshimoto (and therefore his cousin).
References
- Jôkei-In From Japanese Wikipedia
- Imagawa Yoshimoto From Japanese Wikipedia
- Takeda Nobutora From Japanese Wikipedia