Battle of Okehazama (桶狭間の戦い Okehazama-no-tatakai) took place in May of 1560. In the battle, Oda Nobunaga defeated Imagawa Yoshimoto.

Yoshimoto had decided to march his sizable army through Oda territory of Owari to reach Kyoto, the captiol of Japan during the Sengoku era, and gain control of the land. The battle was deceptivly easy to predict: Nobunaga's army was outnumbured ten to one by the Imagawa forces. A frontal assault by the Oda forces would be suicidal, and holding out his castle would only last a few days against the assault, and under these circumstances Oda Nobunaga decided on a surpise ambush on the Imagawa forces. The attack, aided by a sudden rainstorm, came from behind Imagawa lines, catching them completly off guard. Many top officers of the Imagawa, including Yoshimoto himself, were killed.

With thier leader dead, and many of the better officers also killed, the remaining officers defected to other forces. In a short while, the Imagawa faction was destroyed. The victory by Nobunaga was hailed as miraculous, and proved to be his first step to his goal of unification.

One of the officers who would betray the Imagawa was Matsudaira Motoyasu (later to be known as Tokugawa Ieyasu) from Mikawa, with Honda Tadakatsu along with him. He formed his own force in Mikawa, and would later would become an ally of Nobunaga Oda, and the last of the great unifiers.

List of samurai in the battle

Oda side

• Oda Nobunaga
• Shibata Katsuie
• Hattori Kazutada
• Mori Yoshikatsu
• Kinoshita Tokichiro

Imagawa side

• Imagawa Yoshimoto
• Asahina Yasutomo
• Matsudaira Motoyasu
• Naomori li
• Honda Tadakatsu