shogun (hereditary military dictator) who helped promote one of Japan's greatest cultural eras. His attempts to select an heir, however, brought on a dispute that caused the great Ōnin War (1467–77). This conflict not only laid waste the area around the capital at Kyōto and destroyed many of its great architectural treasures but also eliminated the fiction of central control over the outlying regions of the country, thus touching off a century of civil warfare.

Yoshimasa was proclaimed shogun in 1449 at the age of 13, at a time when central control over the countryside had begun to deteriorate, with starvation and misery rampant. When he was only 29 years old, unable to alter conditions, Yoshimasa decided to retire from the shogunate and name his younger brother as his successor. Before the succession could be effected, however, his wife bore a son (1465), whom she demanded be made the heir. In spite of Yoshimasa's attempts to settle the problem peacefully, in 1467 the difficulty became an excuse for war between two rival military factions serving the shogunate. Although the war dragged on until 1477 and ended in a stalemate, Yoshimasa finally abdicated in 1473 in favour of his son. After the boy's death in 1489, Yoshimasa appeased his brother by naming his brother's son as the new shogun.

Though ineffective as shogun, Yoshimasa was a great patron of the arts. After his retirement he built the famous Silver Pavilion (Ginkaku-ji) in the Higashiyama, or Eastern Hills, area of Kyōto. There he practiced the Japanese tea ceremony, which he developed into a fine art, and sponsored many noted artists, potters, and nō (classical dance-drama) performers. Today the Higashiyama period, as this cultural era became known, is considered one of the greatest in Japanese art history.