- Date: 1537-early 1550s
- Japanese: 河東の乱 (Katou no ran)
In 1537, Imagawa Yoshimoto of Suruga province made peace with Takeda Nobutora of Kai, marrying Nobutora's daughter, Shingen's older sister Jôkei-in. At this time, the Takeda had been considering invading Shinano province, and now with Yoshimoto married to the daughter of Nobutora, the Takeda could go forward with the Shinano invasion without having to worry about being attacked from behind by the Imagawa. Obviously the Takeda saw great merit in this political marriage, as they could put all of thier efforts into invasion. On the other hand, for the Imagawa, who until now had been subservient in power to the Hôjô, this alliance meant that they could gain some advantage and independence.
Around this time, the Hôjô and the Takeda were in conflict, and Yoshimoto's peace with the Oda was seen by Hôjô Ujitsuna as a betrayal of sorts, because the Hôjô had supported Yoshimoto in the Imagawa clan succession dispute known as the Hanagura no Ran, and so took this marriage as an affront. The Hôjô attacked the Imagawa, but were repelled. The Hôjô attacked again in 1554. However, in reality, neither side really wanted to fight because they each had their own agenda, and eventually, in the mid-1550s, they made peace with the Hojo-Takeda-Imagawa Alliance.
References
- Kanaya, Shunichiro. Sengoku Jidai ga Omoshiroku Wakaru Hon (戦国時代が面白くわかる本) Japan, 2003
- Joukei-In From Japanese Wikipedia