User:Cckerberos/Rebellion of Uesugi Zenshū

The Rebellion of Uesugi Zenshū (上杉禅秀の乱) was a Muromachi Period war in the Kantō area of Japan in 1416. The rebellion was launched by former Kantō Kanrei Uesugi Zenshū (Ujinori) against Ashikaga Mochiuji, the Kamakura Kubō.

Background
Beginning in the Nanboku-chō Period, the Ashikaga shogunate established the Kamakura-fu to serve as its regional office in the Kantō area. Headed by the Kamakura Kubō, a member of the Ashikaga clan, the office was intended to help maintain shogunal authority over the region. The Kamakura Kubō was supported in this by the Kantō Kanrei, a member of the Uesugi clan. Over the decades, the Kamakura-fu's authority and autonomy expanded, as did the influence and holdings of the Uesugi. With this increase in power, a number of Kamakura Kubō came to seek the position of shogun. Tensions between Kyoto and the Kamakura Kubō grew worse as a result, leading the shogunate to form a stronger relationship with the Uesugi clan as a countermeasure.

Course of the rebellion
By the early 15th century, the position of Kantō Kanrei had come to alternate between two rival branches of the Uesugi known as the Yamanouchi and Inugake. When Ashikaga Mitsukane, the third Kamakura Kubō, died in 1409, he was succeeded by his son Mochiuji. Initially, Uesugi Norisada of the Yamanouchi-Uesugi served as Mochiuji's Kantō Kanrei, but he was overthrown by Uesugi Ujinori of the Inugake-Uesugi in 1411. Ujinori then became close with Mochiuji's uncle Ashikaga Mitsutaka and younger brother Ashikaga Mochinaka (Mitsutaka's adopted son) in the hopes of becoming the true power within the Kamakura-fu rather than the young Mochiuji.

Ashikaga Yoshitsugu was Shogun Ashikaga Yoshimochi's younger brother and had been his main rival to succeed their father as shogun. Although the details are still unknown, a conspiracy against Yoshimochi was gathering in Kyoto at this time, centered around putting Yoshitsugu on the throne. Mochiuji is believed to have made secret contact with the anti-Yoshimochi forces.

Ujinori and Mochiuji came into conflict at a council meeting on April 25, 1415, however, and Ujinori was dismissed as Kantō Kanrei on May 2. Uesugi Norimoto of the Yamanouchi-Uesugi (Norisada's younger brother) was designated as his successor on the 18th. Ujinori conferred with Ashikaga Mitsutaka and Mochinaka and rose in rebellion against Mochiuji in 1416, supported by his sons-in-law Iwamatsu Mitsuzumi, Nasu Sukeyuki, and other local kokujin such as Chiba Kanetane, Nagao Ujiharu, Utsunomiya Mochitsuna, Daijo Mitsumoto, Yamairi Tomoyoshi, Oda Mochiie, Miura Takaaki, Takeda Nobumitsu, Yūki Mitsutomo, and Ashina Morimasa.

Ashikaga Mitsutaka and Ujinori rose up with troops from the Hōjū-in near the palace on the evening of October 2 with the goal of capturing Mochiuji and Norimoto, but Mochiuji successfully fled with his vassals. Afterwards Ujinori and Mitsutaka moved to secure control of Kamakura with their supporters. Although it is believed that the Kantō's powerful warrior families were required to be in attendance in Kamakura at the time, returning to their lands to govern only when needed, it is thought that Ujinori timed the rebellion for a period when Mochiuji's supporters were away from Kamakura.

When a report from Imagawa Norimasa, the shugo of Suruga, reached Kyoto on October 13, it incorrectly stated that Mochiuji and Norisada had been killed. There was chaos within the shogunate as Shogun Yoshimochi was away for the day visiting Inaba-dō. The daimyo in the shogunate met and decided to gather information and wait for Yoshimochi to return that night. Once it had been learned that Mochiuji and Norisada were uninjured and that the fleeing Mochiuji had reached Imagawa Norimasa in Suruga and was requesting aid, Yoshimochi met with the daimyo and decided to aid Mochiuji on the advice of his uncle Ashikaga Mitsuakira.

The forces of Imagawa Norimasa, Uesugi Fusakata, Ogasawara Masayasu and the Satake and Utsunomiya headed to defeat Mitsutaka and Ujinori by order of the shogunate. Ujinori attacked Suruga because of this but was defeated by the Imagawa. The warrior bands of Musashi (such as the Edo and Toyoshima clans), pressured by the Uesugi, then gathered and pushed Ujinori's forces out of the province. Ujinori's army destroyed the Edo-Toyoshima forces at the Battle of Seyahara in 1417, but the Imagawa army took advantage of its absence to invade Sagami. Ujinori, Mitsutaka, and Mochinaka committed suicide at Yukinoshita in Kamakura on January 10. The Inugake-Uesugi were destroyed as a result of their defeat in the war (although a number of Ujinori's sons had become monks and survived, receiving shogunal protection). Takeda Nobumitsu was driven back to his province of Kai, where he committed suicide. Iwamitsu Mitsuzumi was captured and executed.

On the Ashikaga Shogunate
Believing himself to be in danger following Ujinori's death, Yoshitsugu fled Kyoto in 1417 but was quickly captured by Togashi Mitsunari at Takao. He was then imprisoned at Ninna-ji and Shōkoku-ji and forced to become a monk on October 20. Mitsunari's investigation into Yoshitsugu's activities created problems in early November as it found that Ujinori's conspiracy to assassinate Yoshimochi included not just Yoshitsugu, but kanrei Hosokawa Mitsumoto, former kanrei Shiba Yoshinori, Hatakeyama Mitsunori, Akamatsu Yoshinori, Toki Yasumasa, Yamana Tokihiro, and the noblemen Yamashina Noritaka and Hino Mochimitsu as well. Based on this report, Toki Mochiyori (Yasumasa's heir) lost his position as shugo of Ise and Yoshimochi ordered the confinement and banishment of numerous powerful daimyo and noblemen, most notably Mitsumoto.

Yoshitsugu was murdered by Togashi Mitsunari on Yoshimochi's orders in the beginning of 1418. But in November of that year, Mitsunari himself was suddenly banished on suspicion of having conspired with Yoshitsugu and having an affair with Yoshimochi's wife Ringakyoku. This has been said to have been a reverse coup by the powerful shugo daimyo under the Hosokawa against Yoshimochi and Togashi Mitsunari. Mitsunari fled to Koya-san, but was killed by Hatakeyama Mitsuie on February 28, 1419.

On the Kamakura Kubō
The shogunate embarked on punishing Ujinori because it feared cooperation between Yoshitsugu and the Southern Court, not because it truly wanted to support the Kamakura Kubō Mochiuji. Likewise, Mochiuji had long shown himself to be working against the central government's authority, taking advantage of disorder in the shogunate to expand the limits of his authority and strengthen his base against armed uprisings in Kantō and Mutsu. The fact that Ujinori's orphans were protected by the shogunate, even though they were the ones who killed Ujinori, was in consideration of the situation where Mochiuji was resistant to the shogunate. That control of Ashikaga-shō, the origin of the Ashikaga clan, was moved to be directly under the shogunate rather than the Kamakura-fu is thought to have been a restraint on Mochiuji.

The Kazusa no Han'ikki, an ikki centered around the kokujin that were Ujinori's former vassals, broke out in his former province of Kazusa the year following his death. Many of the daimyo who had supported Zenshū stopped attending Mochiuji in Kamakura, fearing his retribution (and in fact, Yamairi Tomoyoshi and Daijo Mitsumoto would be attacked and killed by Mochiuji's forces while serving in Kamakura). Afterwards, Mochiuji acted independently, working to purge those who opposed him in Kantō such as the pro-Ujinori remnants like the Iwamatsu and Satake (Yamairi), and the daimyo of the Kyōto Fuchishū.

Mochiuji's uncle Ashikaga Mitsunao (the Sasagawa Kubo), dispatched to govern southern Mutsu, had had close ties to the Inugake-Uesugi and his relationship with Mochiuji worsened after the rebellion and he worked to make himself independent of the Kamakura-fu.

The shogunate became wary of Mochiuji before long, and clashes of opinion between the Kamakura Kubō and the Kantō Kanrei continued. The Kantō region would continue to be unstable, with the Eikyō Rebellion breaking out in 1438 and the Yūki War in 1440.