Oda Nobunaga was the first of the “three unifiers” who brought about the end of the Sengoku Period (1467–1600). A military genius, he developed new tactics for armies using spears and arquebus guns and also greatly improved castle construction techniques.
When his father died in 1551, Nobunaga was able to consolidate power within his own clan and by 1560 he had taken control of the region around what is now Gifu and Nagoya. In the Battle of Okehazama (1560), Nobunaga defeated an invading force of 25,000 Imagawa samurai with just 3,000 men armed primarily with arquebuses. He captured Inabayama Castle in 1567 and renamed it “Gifu.” For about ten years he expanded the castle and used it as his stronghold until he moved again in 1576 to the newly completed Azuchi Castle in modern-day Shiga prefecture.
As his influence and power rose, Nobunaga grew more ambitious and worked to unify all of Japan under his rule. In 1575, Nobunaga defeated the powerful Takeda clan in a large-scale gun battle at Nagashino. He dominated the Uesugi clan after the death of their leader in 1578 and defeated the forces of Hoganji temple in 1580. In 1581 he took control of Iga province, and in early 1582 he had completely destroyed the Takeda clan.
Akechi Mitsuhide (1528–1582) was in Oda Nobunaga’s inner circle of trusted generals. In June 1582 Nobunaga ordered him to bring reinforcements to a battle in Western Japan, but he instead marched his 13,000 men to Honnoji Temple in Kyoto, where Nobunaga was staying at the time. Mitsuhide betrayed Nobunaga and attacked him. Hopelessly outnumbered and wounded by arrow fire, Nobunaga retreated into the temple’s inner sanctum and committed ritual suicide. Mitsuhide was killed weeks later after the Battle of Yamazaki. Another of Nobunaga’s generals, Toyotomi Hideyoshi (1537–1598), would continue Nobunaga’s work of national unification.