Battle of Anegawa
Azai-Asakura Allied Army
Oda-Tokugawa Allied Army
Date: 6/28 of Genki 1 (1570)
Location: On and around the Ane River in the Azai District of Ōmi Province
Outcome: Miscalculations by the Azai-Asakura forces caused their lines to become too stretched, creating an opportunity for attacks against their flanks that enabled the Oda-Tokugawa forces to prevail in a violent melee over the coure of one summer day.
The Battle of Anegawa occurred on 6/28 of Genki 1 (1570) in and around the Ane River in the Azai District of Ōmi Province. The name of the battle is attributable to the Tokugawa clan, but it was also referred to as the Battle of Nomura by the Oda and Azai clans and the Battle of Mitamura by the Asakura clan based on the locations where the battle unfolded.
Prelude to the battle
After Oda Nobunaga, a sengoku daimyō from Owari Province, killed Imagawa Yoshimoto of Suruga at the Battle of Okehazama, and seized Mino Province from Saitō Tatsuoki, he invaded Ōmi as a step toward marching upon the capital of Kyōto. In advance of the invasion, he had his younger sister, Oichi-no-kata, wed Azai Nagamasa, who governed northern Ōmi, creating a political alliance between the Oda and the Azai. Nobunaga then received reinforcements from the Azai clan, and together defeated their common enemy, Rokkaku Yoshikata, the powerful daimyō of southern Ōmi, at the Battle of Kannonji Castle, whereupon, in 1568, Nobunaga marched to Kyōto to install Ashikaga Yoshiaki as the fifteenth shōgun of the Muromachi bakufu.
Thereafter, in the fourth month of 1570, Nobunaga attacked Asakura Yoshikage in Echizen Province. Yoshikage had earlier rejected calls from Nobunaga to support the march upon Kyōto. Owing to the close relationship between the Asakura and the Azai clans, Nagamasa alienated himself from Nobunaga and had his forces attack the Oda from their rear flank. Caught between opposing forces on both sides, Nobunaga was compelled to retreat, using an escape route through Kanegazaki to withdraw.
Break-out of hostilities
After a temporary respite in the capital to reconstitute his forces, on 5/9, Nobunaga headed toward Gifu. Meanwhile, Asakura Yoshikage and his men set-up an encampment in Tsuruga, managing post-battle affairs and endeavoring to communicate with Azai Nagamasa. On 5/11, with Asakura Kageakira as the commanding general, a large army headed to Ōmi. The Asakura army advanced along with the Azai army to southern Ōmi, joining forces with Rokkaku Yoshikata with the aim of launching a pincer attack against Nobunaga. The plan did not go well. On 5/21, Nobunaga safely returned to Gifu via the Chikusa Ridge, while, on 6/4, the Rokkaku army suffered a rout by Shibata Katsuie and Sakuma Nobumori at the Battle of Yasugawara. The Azai and Asakura forces responded by setting fire to the environs of Tarui and Akasaka, and then fortified Takekurabe Castle and Karuyasuo Fortress, stationing troops to prepare for an assault by the Oda army.
On 6/15, the Asakura army returned to Echizen, but around this time Hori Hidemura and Higuchi Naofusa, who had been stationed at Takekurabe Castle, betrayed the Azai and Asakura by surrendering to Nobunaga, upon which both Takekurabe and Karuyasuo fell to the Oda. Upon receiving this news, on 6/19, Nobunaga departed Gifu and entered Takekurabe Castle that same day. After establishing a camp at Mount Toragomae on 6/21, Nobunaga ordered Mori Yoshinari, Sakai Masahisa, Saitō Toshiharu, Shibata Katsuie, Sakuma Nobumori, Hachiya Yoritaka, Kinoshita Hideyoshi, and Niwa Nagahide to burn down a broad area in the town below Odani Castle. As the rear guard, Nobunaga then led five hundred arquebusiers including Yanada Hiromasa, Chūjō Ietada, and Sassa Narimasa along with thirty archers and retreated.
On 6/24, Nobunaga’s forces surrounded Yokoyama Castle located to the south between Odani Castle and the Ane River, while Nobunaga himself established a base at Ryūgahana. Tokugawa Ieyasu led forces to this location to converge with the Oda army. Meanwhile, a contingent of 8,000 soldiers led by Asakura Kagetake aligned with the Azai arrived. The Asakura forces set-up their base on Mount Ōyori to the east of Odani Castle. An additional 5,000 soldiers under Azai Nagamasa joined them, so that the combined forces totaled 13,000 men.
On 6/27, the Azai-Asakura combined forces departed their base and, before dawn on 6/28, split into two divisions near the Ane River, with one in Nomura and the other in Mitamura. To commence the battle, Tokugawa forces headed toward the soldiers based at Mitamura to the west, while Nobunaga dispatched mounted soldiers including the Western Mino Group of Three (Inaba Yoshimichi, Ujiie Naomoto, and Andō Morinari) toward Nomura to the east. the fighting began around 6:00 AM, with violent clashes as the Azai forces headed toward the Ane River. After noticing that the formation of the combined Azai-Asakura forces became stretched, Ieyasu ordered Sakakibara Yasumasa to attack from the flank.
First, the Asakura army fled in defeat, then the Azai army followed. In the end, the combined Oda and Tokugawa forces killed over 1,100 men en route to victory. The extent of the violent melee is captured in vivid descriptions of the battle as leaving fields of blood and a river of blood. Nobunaga’s forces gave chase to the retreating forces and burned down all of the homes in the foothills of Odani Castle. Concluding that it would be difficult to capture Odani in a single assault, he had the forces pull-back to Yokoyama Castle. Soon thereafter, the defenders at Yokoyama surrendered and Nobunaga assigned Kinoshita Hideyoshi (later known as Toyotomi Hideyoshi) to guard the castle.
Theory of a surprise attack
There is an alternate theory that the Battle of Ane River was a surprise attack by the Asakura and Azai forces. Under this view, the Asakura army departed from Mount Ōyori early in the morning, and then suddenly reappeared with the Azai forces in another location. Having believed the enemy forces had retreated, the Oda proceeded to surround Yokoyama Castle again. The Asakura and Azai then attacked from behind, throwing formations on both sides into disarray.
Consequences of the battle
The Battle of Anegawa caused significant damage to the Azai family. Nagamasa lost many senior retainers who performed key roles, including Endō Naotsune, Azai Masayuki (Nagamasa’s younger brother), Azai Masazumi, Yuge Iezumi, and Imamura Ujinao. Meanwhile, the Asakura clan lost Magara Naotaka, Magara Naozumi (Naotaka’s younger brother), and Magara Takamoto (Naotaka’s son) – three bushō known for wielding massive long swords. In addition to the main battlefield losses, many soldiers on both sides died during the retreat. Sakai Hisatsune, the eldest son of Sakai Masahisa, fought earnestly during the early part of the battle only to be later killed. Notwithstanding their defeat, residual forces of the Asakura and Azai remained a threat in and around Ōmi and Echizen provinces. These men allied with mercenaries associated with the Enryaku Temple from Mount Hiei in addition the Ikkō-ikki, a religious band from the Ishiyama-Hongan Temple. A series of battles unfolded in the Shiga District of Ōmi, known as the Siege of Shiga (Shiga no jin). In the course of these battles, the Oda incurred material losses, including death in battle of commanders such as Oda Nobuharu (Nobunaga’s younger brother), Mori Yoshinari, and Sakai Masahisa.
Nobunaga ordered clean-up operations against residual enemy forces, including burning down the facilities of the Ishiyama-Hongan Temple on Mount Hiei who supported the Azai and Asakura. Nobunaga determined that military force alone would be inadequate to achieve his objectives, so he aimed to incite internal conflict within the Azai family through artifice. An example was the estrangement of Isono Kazumasa, the most decorated soldier for his achievements at the Battle of Anegawa. As a result of the conflict, the territory was divided between north and south. Kazumasa, who defended Sawayama Castle in the Inukami District, was isolated and could not receive provisions for the castle. Hideyoshi then spread a rumor within the Azai family that Kazumasa was colluding with the Oda, causing Nagamasa to be suspicious of Kazumasa and deny three requests from Kazumasa for supplies. Confronted with dwindling provisions, Kazumasa surrendered to the Oda and committed to the elimination of the Azai. A gradual weakening of the Azai and Asakura clans caused them to significantly change their strategy, allying with Takeda Shingen of Kai Province and Kennyo, the head priest of the Hongan Temple, to form an encirclement campaign against Nobunaga.