Kato no ran

• Date: 1537-early 1550s

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.

Unfortunately, this angered Hôjô Ujitsuna, who had supported Yoshimoto in the Imagawa clan succession dispute known as the Hanagura no Ran. At that time, the Hôjô and the Takeda had been in conflict, so Ujitsuna felt Yoshimoto should have been grateful for his support and 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 Jidaga Omoshiroku Wakaru Hon (戦国時代が面白くわかる本) Japan, 2003
• Joukei-In From Japanese Wikipedia