Onin War and Japan's Warring States

In 1467 a quarrel over who would succeed the shogun Ashikaga Yoshimasa turned into open war in Kyoto. Yoshimasa had no son and named his brother Yoshimi as heir, but then his wife Hino Tomiko gave birth to a boy, Yoshihisa. Two powerful deputies, Hosokawa Katsumoto and Yamana Sozen, took opposite sides, each backed by allies from across the country. Their armies fought for ten years in and around the capital, burning temples, mansions and libraries.¹

The Ashikaga shogunate, set up after the Kamakura shogunate fell, relied on regional governors, called shugo, who held large domains and kept their own armies. By the 1460s the shogun's authority was weak. Both Sozen and Katsumoto died in 1473, but fighting dragged on until 1477 and settled nothing. The war spread to the provinces, where local warriors seized land and the shogun became a figurehead. The century that followed is called the Sengoku, or Warring States, period, in which daimyo ruled their own domains and the low overthrew the high, a pattern called gekokujo. Unification came through Oda Nobunaga, Toyotomi Hideyoshi and Tokugawa Ieyasu.¹³