Onin War (1467-1477): Kyoto Burns and Sengoku Japan Begins

The Onin War was a civil war fought mainly in and around Kyoto, the Japanese capital, from 1467 to 1477. It began as a dispute over who would succeed the shogun Ashikaga Yoshimasa and grew into a struggle between two great coalitions of warrior families. The war left much of Kyoto in ashes, destroyed the authority of the Ashikaga shogunate, and is traditionally seen as the start of the Sengoku, or Warring States, period, a century of regional warfare that ended only with the unification of Japan around 1600.

Background: a weakening shogunate

The Ashikaga shogunate, founded in 1336, ruled Japan from the Muromachi district of Kyoto. The shogun was the military ruler, while the emperor kept ceremonial authority. At its height under Ashikaga Yoshimitsu, builder of the Golden Pavilion, the shogunate was strong and prosperous.

Its power, however, depended on the shugo, military governors of provinces who were often also great landholders. The most powerful of them sat on the shogun’s council and lived in Kyoto, and the post of kanrei, the shogun’s chief deputy, rotated among the Hosokawa, Hatakeyama and Shiba families.

During the fifteenth century the shogunate weakened. The sixth shogun, Ashikaga Yoshinori, was assassinated by one of his own governors in 1441. Famine, peasant uprisings demanding debt cancellation and quarrels inside the great families undermined order. Two of the three kanrei families, the Hatakeyama and the Shiba, were split by bitter disputes over who should head them.

The succession dispute

Ashikaga Yoshimasa became shogun as a boy in 1449. He took more interest in art, gardens and the tea ceremony than in government. Lacking a son, in 1464 he persuaded his younger brother Ashikaga Yoshimi, who had been a Buddhist monk, to return to lay life and become his heir.

In 1465 Yoshimasa’s wife, Hino Tomiko, gave birth to a son, Ashikaga Yoshihisa. Tomiko was determined that her child should become shogun, and she sought the support of Yamana Sozen, a powerful warlord whose family governed several provinces in western Japan. Yoshimi, for his part, was backed by Hosokawa Katsumoto, the kanrei and head of the strongest family in the shogun’s council, who was also Sozen’s son-in-law.

The great families lined up behind these two leaders, partly according to their own internal feuds. Rival claimants for the leadership of the Hatakeyama and Shiba houses each sought help from one side or the other, and so the dispute within the shogun’s family became a contest between two national coalitions.

Outbreak of war in Kyoto

The first fighting came early in 1467, when Hatakeyama Masanaga and his cousin Hatakeyama Yoshinari clashed at the Kamigoryo Shrine in northern Kyoto. The imperial court changed the era name to Onin that year, which gave the war its name.

By the summer both sides had brought large armies into the capital. Contemporary chronicles claim that Hosokawa’s Eastern Army had about 160,000 men and Yamana’s Western Army about 110,000, but these figures are certainly exaggerated. The two camps occupied different parts of the city, with Hosokawa holding the area near the shogun’s palace and Yamana’s headquarters to the west, the origin of the name Nishijin, “Western Camp”.

The shogun Yoshimasa stayed in his palace, nominally neutral but effectively under Hosokawa control. In a confusing reversal, Yoshimi left the Eastern camp in 1468 and joined the Western Army, which then treated him as its own shogun. The original cause of the war was thus turned upside down.

A war inside a city

The Onin War was unusual because most of its early fighting took place within the streets of the capital. The armies dug trenches, built wooden towers and earthworks, and fought from block to block. Fires spread across the closely packed wooden city.

Many of Kyoto’s great temples were burned, among them Shokoku-ji, along with the mansions of nobles and warriors and the homes of townspeople. Libraries, paintings and archives were lost. Courtiers and monks fled to the provinces, where they were welcomed by regional lords who wanted to share in capital culture. The Ouchi family’s town of Yamaguchi in western Japan, for example, became known as a “little Kyoto”.

The war also saw the growing use of ashigaru, lightly armed foot soldiers recruited from commoners. Contemporary writers complained that these irregular troops looted and burned freely. In later Sengoku warfare, organised ashigaru armed with spears and, from the 1540s, firearms would become central to Japanese armies.

Stalemate and exhaustion

After the first years of heavy fighting, neither coalition could win. The Western Army was strengthened in 1467 by the arrival of Ouchi Masahiro with a large force from western Japan, but the Eastern side held the shogun and the emperor. The fighting turned into a long, destructive stalemate, while the leaders’ home provinces slipped out of their control.

In 1473 both main leaders died: Yamana Sozen in the spring and Hosokawa Katsumoto a few months later. At the end of that year Yoshimasa handed the office of shogun to his son, the eight-year-old Yoshihisa. In 1474 the heirs of the Yamana and Hosokawa made peace, but other lords kept fighting.

The war in the capital came to an end in late 1477, when Ouchi Masahiro withdrew his army to the west and the remaining Western commanders left Kyoto. Yoshimi was pardoned. No peace treaty settled the underlying disputes, and the Hatakeyama feud continued in the provinces for years.

Key people

Ashikaga Yoshimasa (1436–1490) was the eighth Ashikaga shogun. Politically ineffective, he is better remembered as a patron of the arts. After the war he built a retreat in the eastern hills of Kyoto, later the temple Ginkaku-ji, the “Silver Pavilion”, which became a centre of the refined Higashiyama culture.

Hino Tomiko (1440–1496) was Yoshimasa’s wife and the mother of Yoshihisa. She became one of the wealthiest and most influential figures in Kyoto, and later accounts often blamed her for the war, a view modern historians treat with caution.

Hosokawa Katsumoto (1430–1473) led the Eastern Army. He was kanrei several times and a patron of Zen; he founded the temple Ryoan-ji, famous for its rock garden.

Yamana Sozen (1404–1473), also known as Yamana Mochitoyo, led the Western Army. A veteran warrior, he had helped crush the assassin of the shogun Yoshinori in 1441, which greatly enlarged his family’s lands.

Consequences: the age of the warring states

The most important result of the Onin War was the collapse of central authority. The Ashikaga shoguns survived in Kyoto until 1573, but they no longer controlled the provinces. The shugo who had spent years in the capital found that their deputies and local warriors had taken power at home.

This period is often summed up by the word gekokujo, “the low overcoming the high”: vassals overthrew their lords, and new families rose to power. Regional warlords known as daimyo created independent domains, with their own laws, castles and armies. In some areas local leagues of warriors and farmers governed themselves; in Yamashiro province, around Kyoto, a league expelled the Hatakeyama armies in 1485 and ran the province for several years.

The warring states period ended only with the campaigns of Oda Nobunaga, Toyotomi Hideyoshi and Tokugawa Ieyasu in the late sixteenth century.

The war also changed culture. Kyoto’s Gion Festival was suspended for over three decades and revived in 1500. The spread of courtiers, monks and artists to provincial castle towns carried capital culture such as poetry, tea and Zen arts across Japan.

Myths and facts

Much of the familiar story of the war comes from the Onin ki, the “Chronicle of Onin”, a literary war tale written some decades after the events. Historians also rely on the diaries of courtiers and monks who lived through the fighting. Because the chronicle is dramatic and partisan, scholars treat its speeches, motives and troop numbers with caution.

A popular saying claims that when old Kyoto families speak of “the last war”, they mean the Onin War. This is a joke about the city’s long memory rather than a literal fact, but it reflects how deeply the destruction marked the capital.

It is also often said that the Onin War was simply a quarrel over the shogun’s heir. In reality, the succession dispute was only the spark; the long-running feuds within the great warrior families and the decline of shogunal power were the deeper causes.

Timeline

• 1441: The shogun Ashikaga Yoshinori is assassinated.
• 1449: Ashikaga Yoshimasa becomes shogun.
• 1464: Yoshimasa names his brother Yoshimi as heir.
• 1465: Hino Tomiko gives birth to Ashikaga Yoshihisa.
• 1467, early: Fighting between Hatakeyama rivals breaks out at the Kamigoryo Shrine.
• 1467, summer: Full-scale war between the Eastern and Western Armies begins in Kyoto.
• 1468: Yoshimi defects to the Western Army.
• 1473: Yamana Sozen and Hosokawa Katsumoto both die; Yoshihisa becomes shogun.
• 1474: The Yamana and Hosokawa heirs make peace.
• 1477, late: The last Western armies leave Kyoto, ending the war in the capital.

Why it matters

The Onin War marks the turning point at which Japan’s medieval order of shogun and provincial governors broke down. It devastated Kyoto, scattered its culture across the country and opened a century in which regional warlords fought for survival and supremacy. The unified Japan built by Nobunaga, Hideyoshi and Ieyasu grew directly out of the chaos the war unleashed.