Why was Imagawa Yoshimoto marching toward Kyoto?

Yoshimoto controlled three provinces (Suruga, Totomi, Mikawa) and had consolidated power sufficiently to contemplate a march on the capital. In Sengoku terms, reaching Kyoto with enough force to control the shogun was the ultimate prize — it meant controlling Japan's nominal political authority. With an army estimated at 25,000 (Nobunaga had perhaps 2,000-3,000 at Okehazama), Yoshimoto appeared to have the numbers to do it.

How did Nobunaga defeat Yoshimoto at Okehazama?

Nobunaga launched a surprise attack during a severe thunderstorm. While Yoshimoto's large army rested in the gorge at Okehazama, Nobunaga led a small force in a direct assault under cover of the storm's noise and reduced visibility. The attack hit Yoshimoto's command position directly. Yoshimoto was killed in the fighting — reportedly beheaded after a brief struggle. The battle demonstrated that speed and surprise could overcome numerical disadvantage.

Imagawa Yoshimoto: The Warlord Nobunaga Killed at Okehazama

Imagawa Yoshimoto was one of the most powerful daimyo in Japan in 1560. He controlled three provinces, commanded an army estimated at 25,000 men, and was marching toward Kyoto to seize political control of Japan. Then a 26-year-old Oda Nobunaga launched a surprise attack in a thunderstorm.

Yoshimoto’s death at Okehazama lasted perhaps twenty minutes of fighting. Its consequences shaped the next half-century of Japanese history.

The Imagawa Power Base

The Imagawa were a senior branch of the Ashikaga clan with long-established authority in Suruga province. By the time Yoshimoto consolidated power — after winning an internal succession conflict in 1536 — the Imagawa controlled Suruga, Totomi, and Mikawa: three provinces on the Pacific coast between Kyoto and the east. [history]

Yoshimoto was not merely a military man. The Imagawa cultivated aristocratic culture — Yoshimoto was a practitioner of kemari (court football) and a patron of court refinements. He shaved and painted his teeth black in the aristocratic manner. The Imagawa aspired to be not just powerful warlords but sophisticated lords in the tradition of the great Heian families. [history]

His domain also held a valuable hostage: the young Matsudaira Takechiyo — who would later take the name Tokugawa Ieyasu. Ieyasu spent his formative years in Imagawa custody in Suruga, and the experience shaped the man who would eventually inherit Yoshimoto’s former domain after Okehazama. [history]

The 1554 Alliance

In 1554, Yoshimoto negotiated a tripartite alliance with Takeda Shingen of Kai and Hojo Ujiyasu of Sagami — the three great powers of eastern Japan agreeing not to fight each other. With his eastern flank secure, Yoshimoto could focus on the western direction: toward Kyoto. [history]

The March and Its End

In 1560, Yoshimoto assembled his army — estimates range from 20,000 to 45,000, with 25,000 as a commonly accepted figure — and began the march toward the capital. The road west ran through Owari province, controlled by Oda Nobunaga. Nobunaga had perhaps 2,000 to 3,000 available. [history]

On 12 June 1560, Yoshimoto’s army stopped to rest in the gorge at Okehazama. A severe thunderstorm struck. Nobunaga launched his attack directly into the storm — using the noise and reduced visibility as cover, targeting Yoshimoto’s command position directly. The attack hit before the camp could organise a defence. [history]

Yoshimoto was killed — reportedly in a brief struggle in which he wounded his attacker before being beheaded. The great army, deprived of its commander, began to dissolve. Nobunaga had survived.

Why It Mattered

Okehazama ended the Imagawa threat and freed Nobunaga to look west. It also demonstrated — viscerally — that numerical superiority could be overcome by speed, surprise, and direct targeting of command.

Whether Nobunaga planned the precision strike on Yoshimoto’s position or stumbled into it through aggressive advance is contested by historians. What is not contested: the outcome. The most powerful daimyo in eastern Japan died in a brief ambush in a rainstorm, and the obscure lord of a mid-sized Owari domain began his path to changing Japan.