Siege of Kawagoe Castle

The 1545-1546 Siege of Kawagoe Castle (河越城の戦い) was part of a failed attempt by the Uesugi clan to regain Kawagoe Castle from the Late Hōjō clan in the Sengoku Period of Japan. Uesugi Tomosada of the Ogigayatsu branch of the Uesugi clan was joined by his more powerful relative Uesugi Norimasa, by Ashikaga Haruuji, the Kantō Kubō in Koga, and by a host of anti-Hōjō daimyō from the Kantō region.

Despite an overwhelming attacking force, numbering around 85,000, the 3,000 men in Kawagoe Castle's garrison, led by Hōjō Tsunashige, held off the siege until the relief force arrived. That relief force, numbering only 8,000, was led by Tsunanari's brother, Hōjō Ujiyasu, and a single warrior was sent to sneak past the Uesugi siege lines to inform the garrison of the relief's arrival. Though still strongly outnumbered, ninja spies informed the Hōjō forces that the attackers, Ashikaga Haruuji in particular, had relaxed their vigilance due to their overconfidence in victory.

The Hōjō tried a risky tactic, coordinating a night attack between the garrison and the relieving force. Going against battlefield custom, the samurai were ordered to leave behind any heavy armor, which would slow them down and perhaps reveal their position, and to not bother taking the heads of their defeated enemies. This would deny the warriors much honor, as their triumphs would not be known or recorded, but the intense loyalty of the Hōjō samurai caused them to follow these orders.

The tactic succeeded, and the Hōjō foiled the siege. This defeat for the Uesugi would lead to the near-extinction of the family.