The shogun has forbidden Hosokawa to aid Masanaga, who attacks Yoshiyoshi without him, is defeated, and escapes to Kyoto.

The shogunate has long forbidden battles between daimyo, and this flouting of the rules leads to open fighting between rival daimyo factions and the speedy disintegration of the Muromachi shogunate’s authority.

Hosokawa raises an army in May, seizes the shogunate residence of Hana-no-Gosho, and coerces the shogun into proclaiming for Hosokawa’s side and denouncing Yamana as a rebel.

Ouichi Masahiro, another leading daimyo, supports Yamana by marching his army to Kyoto, rescuing Yoshinao from Hosokawa and proclaiming him the new shogun.

The battle at Kyoto ends in stalemate, but fighting in what is called the Onin War escalates throughout Japan.