Battle of Kuwabara Castle
Date: Sixth and seventh months of Tenbun 11 (1542)
Location: In the environs of Kuwabara Castle in the Suwa District of Shinano Province
Outcome: After a clash near Kuwabara Castle, Suwa Yorishige requested an offer to settle from Takeda Harunobu, which resulted in Yorishige committing seppuku and the Takeda acquiring a portion of the Suwa District.
The Battle of Kuwabara Castle occurred during the sixth and seventh months of Tenbun 11 (1542) in the Suwa District of Shinano. This battle was waged between the army of Takeda Harunobu (the military governor of Kai Province) and the army of Suwa Yorishige (a sengoku daimyō, the nineteenth head of the Suwa clan and lord of Uehara Castle in Shinano). This conflict led to the elimination of the main branch of the Suwa family.
During the Sengoku period, Takeda Nobutora of Kai and the Suwa clan of Shinano entered into an alliance, whereupon the Takeda invaded the Saku and Chiisagata districts and, in 1540, the Takeda, the Suwa, and Murakami Yoshikiyo of Shinano deployed to the Chiisagata District. In the sixth month of 1541, Nobutora was exiled to Suruga by his eldest son, Takeda Harunobu, after which the Takeda clan changed its diplomatic policies.
In the invasion of the Chiisagata District in 1540, Unno Munetsuna (a member of a gōzoku, or wealthy family of influence) made a request to Uesugi Norimasa of Kōzuke Province for reinforcements, and deployed to Shinano. Meanwhile, Suwa Yorishige entered into a settlement with the Uesugi on his own to divide territory without informing the Takeda and Murakami. The Takeda clan regarded this as a breach of their alliance and considered invading the Suwa territory.
Prelude to the battle
In the third month of 1542, Suwa Yorishige allied with Ogasawara Nagatoki (the military governor of Shinano) to invade Kai, but Harunobu repelled the attack in an event known as the Battle of Sezawa. In the era of Yorishige, the Suwa endured successive years of wind and flood damage to their lands from inclement weather. In the midst of continuing military operations, the family was unable to materially expand their territory so, with little to show for their efforts, they began to pursue another course.
This led to a deterioration in relations between the Takeda and the Suwa, marked by skirmishes along the provincial border. Harunobu lured to his side individuals who had grievances with the main branch of the Suwa including Takatō Yoritsugu (of a branch of the Suwa) and the Kanasashi clan who managed the Suwa Grand Shrine. Then, on 6/24, Harunobu made a full-throttle attack against the upper Suwa District.
Details of battle
On 6/29, Harunobu established a main base in Misayama while, on 7/1, the Suwa army confronted them at Yazakihara. The Suwa army was comprised of 150 mounted soldiers and between 700 and 800 foot soldiers, so Yorishige did not have enough military power to confront the combined Takeda and Takatō armies. Consequently, he burned down and abandoned his main base at Uehara Castle and pulled back to the satellite location of Kuwabara Castle. A battle between Kai Province and the Suwa District of Shinano revealed a significant gap in military power, authority, and funding. Moreover, in the course of unifying Kai, the Takeda gained battle experience so were in a clearly advantageous position.
The combined Takeda and Takatō armies pursued Yorishige and, on 7/3, when the Takeda attempted to advance to the entrance to Takahashi below Kuwabara Castle, the Suwa army defended the castle and repelled the attackers.
On 7/4, Yorishige proposed that the Takeda offer a settlement, in response to which Harunobu had Yorishige taken to Kōfu. As a condition of settlement, Yorishige’s life was to be spared but, on 7/21, Harunobu scrapped that and had Yorishige and his younger brother, Suwa Yoritaka, commit seppuku, thereby vanquishing the main branch of the Suwa family.
Although Harunobu had eliminated the Suwa family, this did not mean that he had pacified all of the Suwa District. That is because, after the battle, the Suwa territory was divided along the Miya River with Takatō Yoritsugu who allied with the Takeda during the attack on Suwa Yorishige. However, Yoritsugu was not satisfied with this division of territory so, in the ninth month (just two months after the battle), he invaded the upper Suwa District. This led to a conflict between Harunobu and Yoritsugu known as the Battle of Miyagawa.