Ōnin War
The , also known as the Upheaval of Ōnin and Ōnin-Bunmei war, was a civil war that lasted from 1467 to 1477, during the Muromachi period in Japan. Ōnin refers to the Japanese era during which the war started; the war ended during the Bunmei era. A dispute between a high official, Hosokawa Katsumoto, and a regional lord, Yamana Sōzen, escalated into a nationwide civil war involving the Ashikaga shogunate and a number of daimyō in many regions of Japan. The war initiated the Sengoku period, "the Warring States period". This period was a long, drawn-out struggle for domination by individual daimyō, resulting in a mass power-struggle between the various houses to dominate the whole of Japan. Origin The Ōnin conflict began as a controversy over who would succeed shōgun Ashikaga Yoshimasa. In 1464, Yoshimasa had no heir. He persuaded his younger brother, Ashikaga Yoshimi, to abandon the life of a monk, and named him heir. In 1465, the unanticipated birth of a son to Yoshimasa put these plans in question. The infant, Yoshihisa, led to a succession crisis with two competing factions. On one side was the shōgun and his brother, together with the shōgun's deputy, Hosokawa. On the other side was Yoshihisa's mother, Hino Tomiko, and her ally Yamana, who was the governor of several provinces. Tomiko sought political and military support to rule as regent until the birth of her son, the future shogun Ashikaga Yoshihisa. She secured the support of Yamana Sōzen and other leaders of powerful samurai clans. In contrast to Tomiko and Yamana, Yoshimi had the support of the Hosokawa clan, a powerful clan that had a great influence on the shogunate court. This dispute for succession started the Ōnin War and led to the beginning of the Sengoku period. Hosokawa had always worked closely with the shōguns brother Ashikaga Yoshimi, and supported his claim to the shogunate. Yamana took this as an opportunity to oppose Hosokawa further, supporting the child as heir to the shogunate. War broke out in the city of Kyoto. This was regarded by the Ashikaga shōgun as an act of rebellion, and thus the Ashikaga and their supporters were forced to try to stop it. The Ashikagas tried to prevent the outbreak of war over the next heir, but the situation escalated into a war that designated the leader of the victorious party as the next shōgun. In 1467 the uncertainty had caused a split amongst the warrior clans, and the succession dispute became a pretext for a struggle for military supremacy. In the end, there was no clear-cut winner. The complex array of factional armies simply fought themselves into exhaustion. Battles Hosokawa's Eastern Army of about 85,000 and Yamana's Western Army of about 80,000 were almost evenly matched when mobilized near Kyoto. The fighting started in March when a Hosokawa mansion was burned. Then in May 1467, a Yamana mansion was attacked. In July, according to Sansom, Yoshimasa appointed Hosokawa commanding general in an attempt to "chastise the