Chōkyō War (1487–1505, Ōgigayatsu–Yamanouchi Uesugi Conflict)

Overview

From Chōkyō 1 (1487) to Eishō 2 (1505), the Ōgigayatsu and Yamanouchi branches of the Uesugi fought in the Kantō. This is known as the Chōkyō War. Its main battlefields lay in present-day Isehara, Ranzan, Ogawa, Yorii and Tachikawa.

Origins

In the 7th month of Bunmei 18 (1486), a retainer of Uesugi Sadamasa of the Ōgigayatsu assassinated Ōta Dōkan at Kasuya Residence. In Chōkyō 1 (1487), Uesugi Akisada of the Yamanouchi and a different Uesugi Sadamasa (same reading, written with different characters) seized Kanō Castle in the Ashikaga estate from Nagao Fusakiyo, and the fighting became a full-scale war.

The Three Battles of Chōkyō 2

Three battles were fought in Chōkyō 2 (1488). In the 2nd month, Akisada's army was ambushed and defeated at Sanemaki-hara (Isehara), and Nanasawa Castle fell to the Ōgigayatsu side. In the 6th month, at Sugaya-hara (Ranzan), the Ōgigayatsu side, aided by Nagao Kageharu and Ashikaga Masauji, defeated Akisada. In the 11th month, at Takami-hara (Ogawa) and Takano-hara (Yorii), Sadamasa attacked Hachigata Castle and Akisada was defeated.

The Prolonged Struggle and the Battle of Tachikawara

In Meiō 3 (1494), Uesugi Sadamasa of the Ōgigayatsu died and Uesugi Tomoyoshi succeeded to the house. In Meiō 5 (1496), Akisada allied with Ashikaga Masauji and attacked Odawara Castle, held by Ise Sōzui (Hōjō Sōun).

In the 8th month of Eishō 1 (1504), Akisada began attacking Kawagoe Castle, Tomoyoshi's base. At the Battle of Tachikawara (Tachikawa) on the 27th day of the 9th month, reinforcements from Imagawa Ujichika and Ise Sōzui joined Tomoyoshi's side, and Akisada's side was heavily defeated, with more than 2,000 dead.

Conclusion and Aftermath

In the 3rd month of Eishō 2 (1505), Tomoyoshi surrendered at the camp at Nakano in Musashi, shaved his head and was confined. The war ended there. As a result both Uesugi houses were weakened, and the way was opened for the later Hōjō to advance into the Kantō.