In the spring of 1379, seeing Yoriyuki HOSOKAWA display his uncommon ability in Kyoto, Yoshimasa SHIBA, Yoriyasu TOKI and others requested the dismissal of Yoriyuki to the shogun, Yoshimitsu ASHIKAGA, by conducting Koryaku Coup; and Ujimitsu had an ambition to obtain the position of shogunate and planned to proceed to the capital to attack Yoshimitsu.
1379年春、京都で細川頼之が辣腕を振るっていたことに対して斯波義将や土岐頼康らが将軍・足利義満に対して頼之の解任を求める康暦の政変が起こると、氏満は将軍職への野心を燃やして上洛して義満を討とうとした。