Stories of the Japanese 01298 [Muromachi/Yoshimochi Period] The Zenshu Uesugi Rebellion: Zenshu's Victory
The "Zenshu Uesugi Rebellion" appears in high school Japanese history textbooks, but I had simply thought of it as a rebellion caused by a man named Zenshu Uesugi who had a falling out with Ashikaga Mochiuji. It was only through studying for this series that I learned it was an event of such magnitude.
I am explaining the event known to later generations as the "Zenshu Uesugi Rebellion," but as I have already mentioned, the involvement of the Shogun's younger brother and the Kanrei (shogunal deputy) is clear, so this was not just a coup plan by Zenshu alone. It is a much larger story.
However, for Shogun Yoshimochi, the situation regarding whether he can punish all those involved is extremely difficult. If he tries to eliminate the Hosokawa, Shiba, and Akamatsu clans all at once, there is a possibility of a backlash.
On December 15, 1416 (the 23rd year of Oei), there is a record that Yoshimochi and the Kanrei, Hosokawa Mitsumoto, and others held some kind of consultation. The content is unknown, but it is thought that a heated discussion likely took place regarding how to bring this rebellion to an end.
The following day, December 16, a letter was discovered in which Hino Mochimitsu, who belonged to the Yoshitsugu faction, invited Enryaku-ji and Kofuku-ji temples to rise up. Consequently, Yoshitsugu's treatment was changed from relatively loose house arrest to being moved to a prison cell. Yoshitsugu's punishment was now unavoidable.
While the punishment of Yoshitsugu's faction was being considered in Kyoto, a counter-offensive by the Mochiuji side had begun in the eastern provinces. On December 18, Norimoto Yamanouchi-Uesugi raised an army in Kozuke Province, defeated the Iwamatsu clan, and began moving south. On December 23, Mochiuji himself began moving east along with Suruga Shugo Imagawa Norimasa.
On December 25, Ujimori Nikaido of the Mochiuji side defeated the army of Norikata Inugake-Uesugi at Irumagawa (Sayama City, Saitama Prefecture). By the way, while Norikata Uesugi is famous as the Kanto Kanrei who died in 1394 (the 1st year of Oei), the Norikata Inugake-Uesugi who appears here is Zenshu's son and a different person.
Mochiuji himself also departed from Kawamura Castle (Yamakita Town, Kanagawa Prefecture), broke through the Sagami River, and by the end of December, had set up camp at Fukurojima (Chigasaki City, Kanagawa Prefecture) to prepare for the capture of Kamakura.
With the turn of the year, Mochiuji sent his advance guard, Naokane Isshiki (?-1438), to Fujisawa. In the Battle of Fujisawa in early January 1417 (the 24th year of Oei), the Isshiki forces were defeated by the Zenshu side. They fled north and attempted to join up with Ujimori Nikaido, but on January 5, they were caught by Zenshu, who had been pursuing them at Iidahara (Izumi Ward, Yokohama City), and were defeated once again. Nikaido also moved south to rescue the Isshiki forces, but he too was defeated by Zenshu in the Battle of Seyahara (Seya Ward, Yokohama City).
The Zenshu side was quite strong. Three months after their uprising in October of the previous year, it seems they had been steadily increasing their allies. The various daimyo in the eastern provinces likely sided with Zenshu, thinking, "It seems the Shogunate is going to recognize Zenshu's coup."
However, once they received information that the Shogunate had decided to suppress Zenshu, his situation gradually began to deteriorate.
Since the place name Irumagawa appears, I naturally thought it would be the current Iruma City in Saitama Prefecture, but it seems to be within Sayama City. It is quite difficult because there are cases where it does not match current place names.