The conflict began in 1454 with the assassination of Uesugi Noritada by Kantō kubō Ashikaga Shigeuji.
[1] The Ashikaga, Uesugi, and other clans then leapt to battle, either defending or assaulting Shigeuji.
The Uesugi called for the shogunate to send a new kubō to replace Shigeuji, and in 1459, the shōgun's brother, Ashikaga Masatomo, arrived to take up that position.
Due to their growing power and numbers, the Uesugi clan now split in three branches (Yamanouchi, Ōgigayatsu, and Inukake), named after the localities within the Kantō where they resided.
Fighting in the Kantō between the Ashikaga and Uesugi calmed for about ten years, resuming in 1477 and ending in 1482, with negotiations for peace.