Siege of Yūki
1440 CE.
Shown on the map at 36.308°, 139.886°.
The Yūki War (結城合戦, Yūki Kassen) was a 1440–1441 armed conflict in the Kantō region between the Uesugi clan (and by extension, the Ashikaga Shogunate) and powerful local families who had supported former Kamakura Kubō Ashikaga Mochiuji, most prominently the Yūki clan. It can be considered a continuation of the Eikyō Rebellion that had concluded a year earlier.
Text from the Wikipedia article Yūki War, licensed CC BY-SA 4.0.