Battle of Bōgamine
Date: Twelfth month of 1508
Location: Bōgamine in Sakaigawa in the Yatsushiro District of Kai Province
Synopsis: In the tenth month, Nobutora and his backers defeated Aburakawa Nobuyoshi at the Battle of Katsuyama, bringing to an end a long succession struggle in the Takeda family. Less than two months later, Nobutora confronted Oyamada Yatarō, the landlord of the Gunnai territory, at Bōgamine. Following a nighttime assault, this victory enabled Nobutora to garner control of Kai Province.
The Battle of Bōgamine occurred in the twelfth month of Eishō 5 (1508) at Bōgamine in Sakaigawa in the Yatsushiro District of Kai Province. The conflict was waged between Takeda Nobutora and Oyamada Yatarō, the landlord of the Gunnai territory in Kai.
In the late Muromachi period, Kai Province was beset by conflict fueled by tensions between powerful kokujin, or provincial landowners, in addition to the autocratic rule of the Atobe clan who served as the deputy military governors of the province. In the Sengoku period, Takeda Nobumasa, the sixteenth head of the Kai-Takeda clan, expelled the Atobe clan. Rather than have his lineal heir, Takeda Nobutsuna, succeed to the headship of the clan, Nobumasa favored his second son of a different mother, Aburakawa Nobuyoshi. This invited opposition from Nobutsuna who, in the sixth month of 1491, forced Nobumasa to retire and succeeded to the headship of the clan. This resulted in the division of the Takeda family into factions, with one side supporting Nobutsuna and the other backing Nobuyoshi to become the head of the clan.
On 7/23 of Meiō 1 (1492), Nobutsuna and Kurihara Nobutō (a backer of Nobuyoshi) engaged in a violent clash at Ichikawa. Initially, the formations backing Nobuyoshi (as supported by Nobumasa) proceeded favorably but, from around 1494, the situation reversed and, in 1498, Nobutsuna’s backers gained the advantage, resulting in a settlement. In 1505, Nobumasa died.
On 2/14 of Eishō 4 (1507), Nobutsuna died of illness. He was succeeded by Takeda Nobutora (earlier called Nobunao) who was fourteen years old. Aburakawa Nobuyoshi took advantage of the death of Nobuyoshi and succession by the youthful Nobutora to raise arms from Katsuyama Castle. Nobuyoshi gained backing from Nobumasa’s third son, Iwate Tsunayoshi along with Kurihara Masatane and Oyamada Yatarō. Katsuyama Castle was located in the village of Kamisone near Kōfu in the Yamanashi District of Kai. This was on the left bank of the Fuefuki River on the southern end of the Kōfu Basin near the Nakamichi-ōkan, a road connecting Kai and Suruga provinces.
On 10/4 of Eishō 5 (1508), Nobutora’s supporters departed their base at the Kawada residence to launch a nighttime assault against Katsuyama Castle. This resulted in an overwhelming defeat for the Aburakawa forces, including the death of Nobuyoshi, three of his sons, Iwate Tsunayoshi, and Kurihara Masatane. This event is known as the Battle of Katsuyama.
Course of events
In the twelfth month of 1508, Oyamada Yatarō (Nobutaka), the landlord of the Gunnai territory, invaded Kōfu and confronted Nobutora ay Bōgamine. Initially, the Oyamada army had the advantage, but a surprise nighttime attack by the forces backing Nobutora resulted in the death of Yatarō.
From 1509 to 1510, clashes persisted between Nobutora and Oyamada Nobuari (Etchū-no-kami, the successor to Oyamada Yatarō) until the two sides reconciled after Nobutora had his daughter wed Nobuari.