The Siege of Kakegawa Castle (Imagawa Ujisato's Defense)

The Siege of Kakegawa Castle: The Fall of the Imagawa and the Fate of a 'Weak' Daimyo

In January of the 12th year of Eiroku (1569), the forces of Tokugawa Ieyasu surrounded Kakegawa Castle in Tōtōmi Province (present-day Kakegawa, Shizuoka Prefecture). Garrisoned in the castle was Imagawa Ujisato—the eldest son of Imagawa Yoshimoto, the hegemon of the Tōkaido region, and the eleventh-generation lord of the Imagawa clan.

However, the military forces remaining under Ujisato's command were already on the verge of collapse. Eight years earlier, in the Battle of Okehazama (1560), his father Yoshimoto had been killed in action. In the 11th year of Eiroku (1568), Takeda Shingen, who should have been an ally, began his invasion of Imagawa territories. Under Shingen's assault, the regional lords of Imagawa defected one by one to the Takeda and Tokugawa, and Imagawa's castles fell in rapid succession. Kakegawa Castle was Ujisato's last fortress.

This battle was a vivid illustration of the 'light and shadow' of the Sengoku period. In contrast to Ashikaga Yoshiteru, the shogun who wielded the katana (killed in the Eiroku Incident of 1565), Ujisato was known even then as a 'daimyo who preferred poetry and kemari to the sword.' Though born the head of a samurai house, he was seen as one who undervalued warfare—a reputation that would dog Ujisato throughout his life. His surrender at Kakegawa Castle etched that evaluation into history.

The Legacy of Imagawa Yoshimoto and Ujisato's Succession: A Man Who Became Daimyo at the Worst Possible Moment

Imagawa Yoshimoto (1519–1560) was the mightiest power in the Tōkaido region during the Sengoku period. Controlling the three provinces of Suruga, Tōtōmi, and Mikawa, and called the 'greatest archer of the seaboard route,' Yoshimoto set out in May of the 3rd year of Eiroku (1560) with a large army (estimated at 25,000 to 45,000 men) to march on Kyoto. Along the way, at Okehazama, he was killed in a surprise attack by Oda Nobunaga. He was 42 years old.

Yoshimoto's death was catastrophic for the Imagawa clan. Having suddenly lost a powerful daimyo, the Imagawa saw Matsudaira Motoyasu of Mikawa (the future Tokugawa Ieyasu) declare independence (3rd to 5th year of Eiroku), and they lost Mikawa. Nevertheless, Ujisato managed to maintain his father's territories of Suruga and Tōtōmi, and retained a degree of power.

But the problem lay in Ujisato's own character. Ujisato was fond of kemari, composed waka poetry, and had excellent cultural cultivation. However, in the political acumen and military talent required of a Sengoku daimyo, he fell far short of his father Yoshimoto. His control over his retainers weakened, and the Imagawa clan fractured before Takeda Shingen's invasion (11th year of Eiroku, 1568).

Takeda Shingen's Invasion of Imagawa Territories: The End of an Alliance

In December of the 11th year of Eiroku (1568), Takeda Shingen began his invasion of Suruga. The 'Kōshōson Alliance' of the Takeda, Imagawa, and Hōjō (established in the 23rd year of Tenbun, 1554) collapsed at this point.

There are various theories about Shingen's reasons for invasion, but the most compelling is that the weakening of the Imagawa clan reduced the military value of the alliance, and dividing Imagawa territories between the Takeda and Tokugawa was more pragmatic. Shingen made a secret agreement with Tokugawa Ieyasu and invaded under the plan to divide Imagawa territories between east and west (transitioning from the 'Sōbu Alliance' to the Kōetsu Alliance).

Ujisato could mount no effective resistance to the Takeda invasion. The regional lords of Suruga surrendered to Shingen one after another. Ujisato was driven from Suruga Castle (present-day Shizuoka City) and fled to Kakegawa Castle in Tōtōmi. Suruga fell into Takeda hands.

Ieyasu's Invasion of Tōtōmi and the Siege of Kakegawa Castle

Tokugawa Ieyasu, who had made a secret pact with Takeda Shingen, began his invasion of Tōtōmi. The regional lords of the Imagawa defected to the Tokugawa one after another, and most of Tōtōmi came under Ieyasu's control.

Kakegawa Castle became the last stronghold of the Imagawa. Ujisato held the castle and appealed to Hōjō Ujimasa (Ujisato's brother-in-law; Ujisato's wife, Lady Hayakawa, was Ujimasa's sister) for reinforcements. Hōjō Ujimasa dispatched relief forces, but they were insufficient to break the Tokugawa siege.

The Tokugawa siege of Kakegawa Castle began in January of the 12th year of Eiroku (1569). The castle's defenses were sturdy, and Ieyasu avoided a direct assault, choosing instead to starve the garrison into submission. The siege lasted approximately five months.

Finally, in May of the 12th year of Eiroku, Ujisato concluded a peace accord with Tokugawa Ieyasu. In exchange for preserving Ujisato's life and the continuity of the Imagawa clan (their status as a samurai house was recognized), Ujisato surrendered Kakegawa Castle. Ujisato then fled to Odawara under the protection of the Hōjō clan, together with his wife, Lady Hayakawa.

Imagawa Ujisato and Katana: The Paradox of a Samurai House That Abandoned Warfare

The story of the Siege of Kakegawa Castle and Imagawa Ujisato holds unique significance when viewed through the lens of sword culture.

The Imagawa clan, as the preeminent daimyo family of the Tōkaido, was also renowned for owning and maintaining excellent katana. The blade known as the 'Yoshimoto Samonji' that Nobunaga seized when Yoshimoto was killed at Okehazama is now also called the 'Sōsan Samonji' and is a famous katana in sword connoisseur circles. This blade was taken by Yoshimoto from Miyoshi Masanaga, and after Yoshimoto's death passed from Nobunaga to Toyotomi Hideyoshi to Tokugawa Ieyasu, becoming known as a 'sword of the realm's unifier.'

Yet Ujisato himself, though he inherited this 'legacy of famous swords,' could not embody the 'martial values' that the sword symbolized. Known as a master of kemari, Ujisato has often been evaluated by posterity as a 'cultured man and daimyo ignorant of warfare.'

This evaluation is not entirely fair. Though Ujisato may have lacked the capacity as a Sengoku daimyo, he survived into the Edo period as a cultural figure who loved waka poetry, kemari, and the performing arts, and his cultural refinement was later highly valued. Moreover, under Tokugawa protection, Ujisato enjoyed a long life (died in 1614 at age 77) and received generous treatment from Ieyasu. 'The Imagawa who abandoned warfare,' ironically, survived because of 'the Tokugawa who conquered through warfare.'

The Historical Significance of the Siege of Kakegawa Castle: Redrawing the 'Sword Map' of the Tōkaido

The year the Siege of Kakegawa Castle ended—the 12th year of Eiroku (1569)—was when the power structure of the Tōkaido underwent a fundamental transformation.

Takeda Shingen took control of Suruga, and Tokugawa Ieyasu took control of Tōtōmi. The Imagawa's 'three-province rule' that once governed Mikawa, Tōtōmi, and Suruga completely collapsed. In its place, a new axis of conflict emerged—'Takeda versus Tokugawa'—which would lead to the Battle of Mikatagahara (3rd year of Genki, 1572).

From a sword perspective, it is significant that the collapse of the Imagawa clan resulted in the dispersal and relocation of katana that had belonged to the Imagawa house. Like Yoshimoto's 'Sōsan Samonji,' the process by which famous blades passed to new owners based on the fortunes of battle is a major characteristic of Sengoku-period sword history, and the Siege of Kakegawa Castle forms one chapter in that history.

Furthermore, after this battle, Kakegawa Castle served as the 'cornerstone of Tokugawa rule over Tōtōmi' and later became known as the castle of Yamauchi Kazutoyo (transferred to Tosa after Sekigahara). The history of Kakegawa Castle was forged at the turning point marking 'the end of the Imagawa and the beginning of the Tokugawa.' When Ujisato left the castle, he likely wore a katana—but the 'world of the warrior' that the sword symbolized would no longer accept him.