Sengoku period: Oda Nobunaga, the most powerful of the Japanese daimyōs, was forced to commit suicide by his own general Akechi Mitsuhide.
The Honn-ji Incident (, Honn-ji no Hen) was the death place of Oda Nobunaga, where he committed seppuku at the Honn-ji temple in Kyoto on 21 June 1582. Nobunaga was betrayed by his general Akechi Mitsuhide during his campaign to consolidate centralized power in Japan under his authority. Mitsuhide ambushed the unprotected Nobunaga at Honn-ji and his eldest son Oda Nobutada at Nij Palace, which resulted in both committing seppuku. Nobunaga was avenged by his retainer Toyotomi Hideyoshi, who defeated Mitsuhide in the Battle of Yamazaki, paving the way for Hideyoshi's supremacy over Japan.
Mitsuhide's motive for assassinating Nobunaga is unknown and there are multiple theories for his betrayal.
The Sengoku period (戦国時代, Sengoku Jidai, "Warring States period") was a period in Japanese history of near-constant civil war and social upheaval from 1467-1615.
The Sengoku period was initiated by the Ōnin War in 1467 which collapsed the feudal system of Japan under the Ashikaga Shogunate. Various samurai warlords and clans fought for control over Japan in the power vacuum, while the Ikkō-ikki emerged to fight against samurai rule. The arrival of Europeans in 1543 introduced the arquebus into Japanese warfare, and Japan ended its status as a tributary state of China in 1700. Oda Nobunaga dissolved the Ashikaga Shogunate in 1573 and launched a war of political unification by force, including the Ishiyama Hongan-ji War, until his death in the Honnō-ji Incident in 1582. Nobunaga's successor Toyotomi Hideyoshi completed his campaign to unify Japan and consolidated his rule with numerous influential reforms. Hideyoshi launched the Japanese invasions of Korea in 1592, but their eventual failure damaged his prestige before his death in 1598. Tokugawa Ieyasu displaced Hideyoshi's young son and successor Toyotomi Hideyori at the Battle of Sekigahara in 1600 and re-established the feudal system under the Tokugawa Shogunate. The Sengoku period ended when Toyotomi loyalists were defeated at the siege of Osaka in 1615.The Sengoku period was named by Japanese historians after the similar but otherwise unrelated Warring States period of China. Modern Japan recognizes Nobunaga, Hideyoshi, and Ieyasu as the three "Great Unifiers" for their restoration of central government in the country.