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The Battle of Poyang Lake
The Onin War

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The Culture of Civil War in Kyoto

War in Japan 1467-1615

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Japan's TA-Operation: A Blueprint for Disaster 
The Onin War (Onin no Jidai)
by Joshua Gilbert

The Onin War, (so called because it occurred in the regnal year Onin 1), was the catalyst that sparked the century long period of Japanese history known as the Sengoku Jidai, the "Age of the Country at War". What began originally as a dispute between a father and his son-in-law, became an eleven year war that trashed the once great city of Kyoto and sparked an era of bloodshed that remains famous to this day.

The Onin War began because of the weakness of one Shogun. In 1464, Ashikaga Yoshimasa, the 8th member of the Ashikaga clan to hold the title Seii-Taishogun, and a man renowned for his focus on tea parties and poetry, wanted to retire but had no son. He decided to instead make his younger brother, Yoshimi, his heir. However Yoshimi was a Buddhist monk, so the Shogun had to first drag his brother out of the monastery in order to make him his heir.

But one year later in 1465, his wife Tomiko, bore him a son. Overjoyed, the Shogun made his infant son Yoshihisa his heir instead. At the same time two of the most powerful men in Kyoto which was the capital at the time, were in the midst of a feud. On one side there was Yamana Sozen, nicknamed Red Monk, a Buddhist monk who was famous for turning red when angry. On the other side was his son-in-law Hosokawa Katsumoto, one of the Three Butlers of the Ashikaga clan (the other two were the Shiba and Hatakeyama clans).

These two men had been engaged in a feud since the 1450s after they had meddled in the succession disputes of the Hatakeyama and Shiba families. Now they had another dispute in which to outmaneuver each other, this time involving the highest office in Japan. This was the leading cause of the war to come. Sozen acted first by declaring his backing for the infant Yoshihisa. Katsumoto threw his backing behind the Shogun's brother, Yoshimi. Both men summoned support from family relations and vassals, and soon the entire capital district of Yamashiro was chocked with Yamana and Hosokawa supporters. The armies numbered 80,000 and 85,000 respectively, the largest yet seen in Japanese history. Yet both men were reluctant to dive into a war. In 1467 Yamana Sozen called in the powerful warlord Ouchi Masahiro with another 20,000 troops. Then in February, a Hosokawa mansion "mysteriously" went up in flames. The war was on.

The Onin War, had begun. The Hosokawa retaliated for the destruction of their mansion in April when samurai, loyal to them, attacked a Yamana rice shipment. In May rumors abounded that Yamana Sozen was going to attack the Imperial Palace. Hosokawa Katsumoto decided to act regardless of the truthfulness of these rumors and moved Emperor Go-Tsuchimikado, Retired Emperor Go-Hanazono, and the entire Imperial family out of the Palace to the headquarters of the Shogunate in Muromachi District. As it turned out Hosokawa had made the right for Yamana did launch an attack on the Imperial Palace .

At the end of the month, Hosokawa supporters burned the mansion of Yamana general Isshiki, along with the entire block to the ground. The Yamana counterattack was fierce, and the war, which until this point had been merely a series of raid and counter raid, now intensified into a full-fledged war in the streets. By July the fighting was so devastating that all of northern Kyoto was in ruins and the remainder of the city resembled the battlefields of the centuries later First World War in Europe. The battle for Shokokuji in October, in which Yamana Sozen himself led an attack on the Hosokawa positions inside a Buddhist monastery, exemplified the carnage. There were enough enemy heads to fill eight carts. By September anyone who could abandon the city did so, even while more reinforcements for the warring factions flowed in.

By early 1468, a calm came over Kyoto. Both sides rested but kept watch each other from across their respective trenches. Hosokawa then resumed hostilities, bringing in trebuchets and using them to fling rocks and exploding bombs into Yamana territory. Sometime later Hosokawa Katsumoto scored a major political coup when he was able to convince both Shogun Ashikaga Yoshimasa and the Emperor to denounce the Yamana as rebels. With the official backing of both Shogun and the Emperor, the Hosokawa now held the moral high ground in the conflict. Any who supported Yamana Sozen did so at the danger of being declared a traitor to the Emperor.

At first, Yamana Sozen treated his branding with indifference. He had the support of such men as Ouchi Masahiro and several great clans as well and he would be able to get the ruling reversed later. Carnage and destruction continued for several years without any sign of letting up. Even the deaths of Hosokawa Katsumoto and Yamana Sozen had little effect on the war.

What had started as a personal spat had spiraled beyond all control. In 1475 Ashikaga Yoshimasa, previously caught up in his little world of poetry and tea, asserted some authority and began to order the various shugo daimyo, (feudal lords who acted as deputies for the Shogun), on both sides, out of Kyoto. Many shugo obeyed the Shogun and began to disengage. However the fighting would continue until 1477, as some stubbornly refused to give up. Ouchi Masahiro, the great champion of Ashikaga Yoshihisa's cause, finally brought the war to a close when he too finally agreed to the Shogun's will and left for home in Yamaguchi. As one last act of defiance he burned his section of Kyoto, the last one reasonably intact, to the ground as he left, later blaming it on his common soldiers. With the pull out of the Ouchi and their vassals from the conflict the eleven year long Onin War ended, not because one side achieved victory, but because both sides simply did not have the strength to continue anymore.

But much more happened in the aftermath of the war. Ashikaga Yoshimasa did little to help as he slid once more back into his private world. With the departure of the last soldiers, mobs descended on the city It would be several years before peace was restored. The chaos in Kyoto had a much larger effect than expected as the fires of war spread into the countryside. Villages banded together under the Ji-Samurai (lesser samurai with common roots), forming armed bands called Ikki which soon mutated from mobs of peasants into disciplined armies. The rise of the Ikki and the continued chaos in Yamashiro (the Hatakeyama clan tore the province apart in a family feud) would soon prove to be just the beginning of one Japan's bloodiest periods. The century long Sengoku Jidai had begun.

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Copyright © 2007 Joshua Gilbert

Written by Joshua Gilbert. If you have questions or comments on this article, please contact Joshua Gilbert at:

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Published online: 02/11/2007.

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