1554: The Formation of the Kai-Sagami-Suruga Triple Alliance
Takeda Harunobu, Hōjō Ujiyasu, and Imagawa Yoshimoto formed the Kai-Sagami-Suruga Triple Alliance, sealed through a series of marriages between their children. With this pact among three eastern daimyo who had long fought one another, each lord was freed from worrying about his rear, allowing them to concentrate their strength on northern Shinano, the Kantō, and Owari respectively.
Events this year
1/24
今川方が築いた村木砦を、織田・水野連合軍が三方から攻め、鉄砲を用いて数時間で今川方を降伏させた。
Sources 東浦町観光協会「村木砦の戦い」
Month 6
Mōri Motonari, who had broken with the Suo clan, defeated Miyagawa Kai-no-kami of the Suo forces at Oshikibata. This victory led to the Battle of Miyoshima the following year, 1555.
The Takeda, Hōjō, and Imagawa established an alliance through marriages among their children.
Hōjō Ujiyasu, Takeda Harunobu, and Imagawa Yoshimoto settled their dispute over the Kato through intermarriage and established the Kō-Sō-Sen (Takeda-Hōjō-Imagawa) Tripartite Alliance. The marriages of Lady Hayakawa and the Yellow Plum Abbess bound the three families' heirs.