Battles & Wars › Gunpowder empires
Sengoku period (Japan's Warring States)
1467–1615· War· Asia & Pacific
Well documentedSolid records, physical evidence or scientific consensus.
A century and a half of civil war in Japan, from the Ōnin War to the Tokugawa victory at Osaka.
See it on the Battles & Wars map →What happened
After the Ōnin War (1467–1477) wrecked Kyoto and the Ashikaga shoguns' authority, Japan split among warring regional lords called daimyo. Vassals often overthrew their masters, a pattern called gekokujō, 'the low overthrowing the high'. Armies grew to tens of thousands, built around ashigaru foot soldiers with spears and, after Portuguese traders brought matchlocks in 1543, guns. Three unifiers, Oda Nobunaga, Toyotomi Hideyoshi and Tokugawa Ieyasu, ended it; the siege of Osaka in 1615 closed the era.
Why it matters
It produced the army and castle-building skills that Hideyoshi turned on Korea in 1592, and the Tokugawa order that kept Japan largely at peace for over 250 years.
How we know
Abundant records: daimyo letters and house laws, chronicles such as the Shinchō Kōki on Nobunaga, Jesuit missionaries' reports, surviving castles, and painted battle screens.
Still debated
Its start and end dates are conventions. Historians debate how chaotic it really was, since regional lords were also building effective states.
Inside this (2)
Connections (4)
▸Sengoku period (Japan's Warring States) was effectively decided at Battle of SekigaharaWell documented
The connection
After Hideyoshi died in 1598, the regents he left split. Tokugawa Ieyasu's Eastern Army defeated the Western Army, loyal to the Toyotomi heir, at Sekigahara in 1600, helped by key defections. Ieyasu became shogun in 1603. The Toyotomi held Osaka until Ieyasu's sieges of 1614–1615 finished them.
When and how
Sekigahara, central Japan, October 21, 1600; Tokugawa Ieyasu against Ishida Mitsunari's coalition.
How we know
Daimyo letters, Tokugawa records and many contemporary accounts document the battle, the defections and the outcome.
Debates and open questions
Historians date the era's end variously to 1590, 1600, 1603 or 1615. Some argue the defections were arranged well before the battle.
▸Sengoku period (Japan's Warring States) forged the battle-hardened army that launched Imjin War (Japanese invasions of Korea)Well documented
The connection
A century of civil war gave Japan large, experienced armies with many thousands of matchlock guns and commanders skilled in siege warfare. Once Hideyoshi had unified the country, he turned these forces, and his restless daimyo, outward, landing about 150,000 men in Korea in 1592.
When and how
Japan, 1467–1590; invasion launched from Nagoya Castle in Kyushu, landing at Busan in May 1592.
How we know
Japanese muster rolls, Korean and Chinese records, and Jesuit letters from Japan describe the army's size and weapons.
Debates and open questions
Why Hideyoshi invaded is debated: ambition to conquer Ming China, a way to occupy and reward his daimyo, or control of trade.
▸Toyotomi Hideyoshi unified Japan at the end of Sengoku period (Japan's Warring States)Well documented
The connection
Rising from foot soldier under Oda Nobunaga, Hideyoshi took over after Nobunaga's death in 1582. By 1590, after subduing the Shimazu of Kyushu and the Hōjō of eastern Japan, he ruled the whole country. His sword hunt and land surveys disarmed peasants and fixed social classes, removing the conditions that fed constant war.
When and how
Japan, 1582–1590; key steps were Yamazaki (1582), the Kyushu campaign (1587) and the siege of Odawara (1590).
How we know
Hideyoshi's own edicts, such as the 1588 sword hunt order, and land survey records survive, along with chronicles and letters.
Debates and open questions
His unification was incomplete: he ruled through powerful daimyo rather than abolishing them, which left room for Tokugawa Ieyasu to take over.
▸Battle of Nagashino was a turning point of Sengoku period (Japan's Warring States)Mostly agreed
The connection
Nagashino destroyed much of the Takeda clan's leadership, removing one of Oda Nobunaga's most dangerous rivals in eastern Japan. It freed Nobunaga to push west and showed that guns and field works could beat even famous warrior clans.
When and how
Shitaragahara, near Nagashino Castle, Mikawa province, June 28, 1575; Oda Nobunaga and Tokugawa Ieyasu against Takeda Katsuyori.
How sure are we?
Chronicles record many senior Takeda commanders killed, and the clan's continued decline until its destruction in 1582.
Debates and open questions
Some historians argue the Takeda were already weakening and that the battle's fame was inflated by later storytelling and films such as Kurosawa's Kagemusha.