The Battle of Kamimura occurred in the twelfth month of Genki 1 (1570).  The conflict arose during a march by the Takeda army toward Mikawa Province (the primary base of the Tokugawa clan) as the Takeda sought to expand their reach beyond Kai and Shinano provinces.  After invading the village of Kamimura in the Ena District of eastern Mino which was held by the Tōyama clan, the Takeda clashed with allied forces of the Tōyama and Tokugawa.

Background

In 1568, Matsudaira Gensaburō (Matsudaira Yasutoshi) was sent by the Tokugawa family as a hostage to the Takeda family, however, in 1570, Gensaburō escaped to Kōshū.  Gensaburō was sheltered by Akiyama Torashige so, in the twelfth month of 1570, Torashige led 3,000 mounted soldiers through the territory of the Tōyama clan in eastern Mino toward the territory of the Tokugawa in Oku-Mikawa.  At the time, powerful local clans known as the Yamaga-sanpōshū of Oku-Mikawa were retainers of the Tokugawa, but viewed the Takeda clan as superior and were colluding with them.  Moreover, the Iwamura-Tōyama clan had previously served the Takeda and, around this time, the younger aunt of Oda Nobunaga named Otsuya-no-kata was the wife of Tōyama Kagetō, the lord of Iwamura Castle allied with the Oda.

Course of events

The Tōyama clan had Tōyama Kageyuki, lord of Akechi Castle, serve as the commander-in-chief of an army including Tōyama Tomokatsu of Iibama Castle, Yoshimura Genzō of Sentanbayashi Castle, Tōyama Uma-no-suke Gorō Tsunekage of Kushihara Castle, Ori Mitsutsugu of Ori Castle, Hirai Kunai-shōyū Mitsuyuki of Takayama Castle, and Tōyama [Unknown] of Agi Castle.  In addition, the Tokugawa clan dispatched members of the Yamaga-sanpōshū and the Mikawa-shū for a total of 5,000 forces.

Tōyama Kageyuki placed troops on each route including at Myōshō fortress in Iidabora, Maeda fortress in Kamimura, and Urushihara Castle in Urushihara.  Kageyuki himself exercised his command from Iwaido fortress.  The Takeda (Akiyama) army split into three units with the main force traveling from the village of Neba over the Ōga Ridge through Ozasahara to Maeda fortress.  The remaining two units aimed to go from the village of Hiraya to Myōshō fortress, and from Kodako to Urushihara Castle.  On 12/28, at the 隘峡の地, 1,000 members of the Kushihara-Tōyama clan initiated hostilities by attacking the Mochizuki forces of the Takeda (Akiyama) army.  In the beginning, the Mochizuki forces appeared to fall back so the Kushihara forces used the opportunity to press forward but the Mochizuki forces held their ground in a favorable location, and spread their forces out to the left and right, whereupon the Hara and Shibayama forces attacked the Kushihara from both flanks.  Meanwhile, the Mochizuki launched a frontal attack, resulting in a defeat for the Kushihara.  A second division of the Tōyama clan attempted to fight in lieu of the Kushihara, but were met with a ferocious attack by the opposing forces, causing them to soon collapse.  Tōyama Kageyuki, the commander-in-chief, prepared to fight but a vanguard of 500 Akiyama forces launched a surprise attack from behind Kageyuki, resulting in a pincer from front and back.  Kageyuki fought valiantly, but, before long, the family members and supporters of the Tōyama clan withdrew in defeat.  Kageyuki, along with five or six soldiers, opened a path to escape, after which he killed himself in the mountains of Urushihara.  Finally, among the 2,500 soldiers dispatched by the Tokugawa from the Yamagata-sanpōshū and the Mikawa-shū, Okudaira Sadayoshi and others were colluding with the Takeda and, after witnessing the annihilation of the Tōyama, retreated with almost no fighting.

Battle of Kodako

The Tōyama clan notified Oda Nobunaga at Gifu Castle in advance that Takeda (Akiyama) forces were approaching Mino Province so Nobunaga sent Akechi Mitsukado (Miyake Chōkansai) and forces under his command.  On 12/29, these forces fought against the Akiyama forces at the village of Kodako on the border of Mino and Mikawa provinces.  Mitsukado understood the battle posture of the Akiyama, so behind the scenes he set four or five ambushes and ousted them by attacking with fire.  After violent conflict over a period of three days, the Alikaya forces lost and withdrew to Shinano Province.