Battle of Kitsuregawa-Sōtomezaka
Date: 9/17 of Tenbun 18 (1549)
Location: Sōtomezaka and along the Kitsure River in Shimotsuke Province
Synopsis: Nasu Takasuke led 300 soldiers to invade the territory of the Utsunomiya. Utsunomiya Hisatsuna then led an army of 2,500 men to deploy to the Kitsure River to intercept them. Owing to the numbers, the Utsunomiya had the initial advantage, but ambushes by the Nasu wreaked havoc on them while Hisatsuna was shot by an arrow and died on the battlefield, resulting in victory for the Nasu army.
The Battle of Kitsuregawa-Sōtomezaka occurred on 9/17 of Tenbun 18 (1549) in Sōtomezaka and along the Kitsure River in Shimotsuke Province. The conflict was waged between the Utsunomiya army led by Utsunomiya Hisatsuna (a daimyō and the twentieth head of the Utsunomiya clan) and the Nasu army led by Nasu Takasuke (a sengoku daimyō and the nineteenth head of the Nasu clan).
Course of events
Utsunomiya Hisatsuna, a daimyō of Shimotsuke Province and the twentieth head of the Utsunomiya clan, overcame internal conflict known as the Tenbun Discord, and took steps such as sending Takasada (the third son of Mashiko Katsumune) to the Haga clan (known as Haga Takasada), thereby achieving a period of stability in the family. New challenges, however, arose and, owing to an attack on the Utsunomiya by a retainer of the Yūki clan named Mizunoya Masamura, Hisatsuna lost some of his retainers including Nakamura Genkaku and Yagioka Sadaie. The disarray provided an opportunity for a retainer named Mibu Tsunafusa to gain prominence within the Utsunomiya. Members of the family including the Mumo and Matsuno clans rebelled against the Satake clan while the Shionoya clan rebelled against the Nasu clan. As a result, these clans began to distance themselves from control by the Utsunomiya. This prompted Hisatsuna to seek a restoration of the authority of the family.
Meanwhile, Nasu Takasuke, a sengoku daimyō of the Nasu District of Shimotsuke, desired to attack the Utsunomiya, and, following the Tenbun Discord, enticed Haga Takateru (the son of Haga Takatsune who had fled to Shirakawa) to join, using him as a pretext to attack the Utsunomiya.
On 9/17 of Tenbun 18 (1549), Takasuke led 300 soldiers to invade the territory of the Utsunomiya. As a result, upon orders from Ashikaga Haruuji, the Koga kubō, Hisatsuna led an army of 2,500 men to deploy to the Kitsure River and engage in battle against the Nasu forces.
Initially, the Utsunomiya enjoyed an advantage based on their superior numbers, so Takasuke used troops lying in ambush in Sōtomezaka to create havoc for the Utsunomiya army, reversing the tide of the battle in favor of the Nasu. Takō Nagatomo (a retainer of the Utsunomiya), Michikawa Tadachika (a retainer of the Kasama), and the Yokota brothers (five sons of Yokota Tsunamura who were retainers of the Yokota) fought valiantly, halting the assault by the Nasu army, but Tadachika and the Yokota brothers were killed in action. These individuals are known as the Five Brothers of the Yokota.
In an effort to control his army amidst the chaos, Hisatsuna went to the front lines of the battle but died after being struck in the chest by an arrow shot by Ayugase Sanemitsu, a retainer of Iono Sukenobu. The battle ended in victory for the Nasu army led by Takasuke.
After the death in battle of Hisatsuna, a veteran of the Utsunomiya clan named Mibu Tsunafusa rose-up and seized control of Utsunomiya Castle. Inside the castle was a young Ise Jumaru (later known as Utsunomiya Hirotsuna) who was taken by Haga Takasada to safety to the base of the Haga clan at Mooka Castle.
After becoming the lord of Utsunomiya Castle, Tsunafusa invited Haga Takateru to use as his puppet while maintaining a grip on power. Senior retainers of the Utsunomiya such as Shionoya Yoshitaka were compelled to submit to Tsunafusa. Nasu Takasuke joined with Tsunafusa while the Utsunomiya clan faced the threat of extinction.