Battle of Anegawa

On June 28, Genki 1 (1570), the "Battle of Anegawa" fought on the bank of the Anegawa river in Sakata-gun, Ōmi Province, was a decisive field battle of the Sengoku period, where the allied forces of Oda Nobunaga and Tokugawa Ieyasu clashed with the allied forces of Asai Nagamasa and Asakura Yoshikage. This battle marked the apex of resistance from Northern Ōmi and Echizen against Nobunaga's strategy for national unification, and became a turning point announcing the practical end of the Asai-Asakura alliance.

**[Background—From the Retreat at Kanegasaki to Anegawa]**

The direct cause of the Battle of Anegawa lay in the "Retreat at Kanegasaki" in April of the same year. Nobunaga advanced into Echizen to attack Asakura Yoshikage, but Asai Nagamasa, the husband of his sister Oichi no kata, suddenly turned against Nobunaga and allied with Asakura, threatening the rear of Nobunaga's army. Nobunaga was forced to retreat with his life barely intact; it was Hanbei Hideyoshi (later Toyotomi Hideyoshi) and Akechi Mitsuhide serving as rear guard who saved him from this crisis.

After the retreat, Nobunaga reorganized his forces to overthrow Asai Nagamasa and sought military reinforcements from Tokugawa Ieyasu. Ieyasu readily agreed and joined forces with the Oda army. At the end of June, the two armies were positioned on the north bank of the Anegawa, overlooking Odani Castle.

**[Progress of Battle—The Vigor of the Tokugawa Forces]**

In the early morning of June 28, the two armies faced each other across the Anegawa. Nobunaga adopted a formation in which he personally led the Oda army against the Asai forces while Ieyasu led the Tokugawa army against the Asakura forces.

Initially, the Asakura forces held a numerical advantage and pressed the left flank of the Tokugawa army. What reversed this critical situation was the fierce fighting of Tokugawa retainers Sakakibara Yasumasa and Naitō Masashige. Yasumasa struck at the flank of the Asakura forces, suddenly reversing the disadvantageous battle situation. Through this achievement, Sakakibara Yasumasa established his reputation as one of the Tokugawa Four Heavenly Kings.

Meanwhile, the direct confrontation between the Oda and Asai armies was extraordinarily intense. Asai Nagamasa was known as a brave and resolute commander, and his officers and soldiers were of high quality. However, as the Asakura forces collapsed, the flank of the Asai forces was also struck, and ultimately the Asai-Asakura allied forces suffered a major blow and were forced to retreat.

According to records after the battle, the Asai-Asakura side suffered thousands of casualties, while the Oda-Tokugawa forces sustained relatively light losses.

**[The Battle of Anegawa from the Perspective of Japanese Swords—The Ferocity of Close-Quarters Combat]**

The Battle of Anegawa was notable for the particularly fierce close combat with swords and spears due to its character as a field battle "on the riverbed." Although this was an era when firearms were beginning to spread across the battlefield, in a field battle with armies crossing a river to face each other, close-quarters combat remained a significant proportion, and the practical significance of the sword retained strong presence.

Regarding the sword culture of the Asai clan, connections with swordsmiths of Northern Ōmi are transmitted from the time of Asai Ryōsei, the great-grandfather of Nagamasa. In Ōmi Province there existed a group of swordsmiths called the "Ōmi school," and swords tracing their origin to the "Ko-Aoe" from the late Heian period through the Kamakura period were valued by the warlords of Northern Ōmi.

Particularly noteworthy is the "sworn-brother" relationship between Oda Nobunaga and Asai Nagamasa, and the possibility that this was expressed in the form of exchange of renowned swords. Among Sengoku daimyō, there was a custom of exchanging famous swords when concluding alliances, and it is conjectured that such sword exchange occurred in the marriage between Nobunaga and Nagamasa. However, in this battle, these former allies found themselves drawing swords against each other.

The famous sword "Yoshimoto Samonji" reportedly possessed by Nobunaga is known to have been brought back as war booty, the sword of Imagawa Yoshimoto whom he defeated at Okehazama. Such movement of famous swords on the battlefield was not uncommon in the Sengoku period. In the intense battle of Anegawa, the swords worn by warlords were used as instruments of fierce close-quarters combat.

**[Asai Nagamasa and Odani Castle—The Bond of Sword and Castle]**

After the defeat at Anegawa, Asai Nagamasa barricaded himself in Odani Castle, his stronghold in Northern Ōmi. Odani Castle was a steep mountain fortress with defensive capacity of the highest standard at that time. However, the defeat at Anegawa greatly diminished Nagamasa's power, and his relationship with Asakura Yoshikage changed.

Nagamasa's wife was Oichi no kata, the sister of Oda Nobunaga, and the couple had three daughters: Chacha, Hatsu, and Gō. These three sisters would later be remembered in Sengoku history as the "Asai Three Sisters." Chacha became a consort of Toyotomi Hideyoshi and as Yodo-dono, the mother of Toyotomi Hideyori, came to occupy a central position in the great flow of history leading to the Osaka Campaign.

**[Sakakibara Yasumasa and the Swords of the Tokugawa]**

Sakakibara Yasumasa, who achieved the greatest distinction at the Battle of Anegawa, was a commander counted among the Tokugawa Four Heavenly Kings alongside Sakai Tadatsugu, Honda Tadakatsu, and Ii Naomasa. Yasumasa's military exploits extended beyond Anegawa to the Komaki-Nagakute War and the Battle of Sekigahara.

The corps of Tokugawa commanders were known to possess high discernment regarding swords. Ieyasu carefully selected his own sword collection, and after the establishment of the Edo shogunate, such prominent treasures as Masamune, Yukimitsu, and Yoshimoto Samonji were managed as "swords of the shogunal house." The swords worn by the Tokugawa commanders who distinguished themselves at the Battle of Anegawa were likewise mostly superior works forged by swordsmiths of the Tōkai and Mikawa regions, and these became historical materials that later sword collectors would pursue.

**[Historical Significance of the Battle—A Signpost Toward the Destruction of Asai and Asakura]**

The victory of the Oda-Tokugawa forces at the Battle of Anegawa caused the practical collapse of the Asai-Asakura alliance. After this battle, Nobunaga faced what was called the "Encirclement Networks" of combined resistance from Takeda Shingen, the Hongan-ji, Asai, and Asakura, but adopted a policy of defeating each enemy individually.

Asai Nagamasa, in the eighth month of Genki 4 (1573), committed suicide in the total assault on Odani Castle by Nobunaga's forces, and the Asai clan was destroyed. Asakura Yoshikage was also destroyed in the same year—three years after the Battle of Anegawa.

This battle occupies a position at the end of an era when the Japanese sword was most intensely used as a weapon in actual combat. Thereafter, as exemplified by Nobunaga's large-scale deployment of firearms at the Battle of Nagashino (1575), the proportion of close-quarters combat on the battlefield gradually diminished. However, the fighting of swords and spears exchanged on the banks of Anegawa remains etched in the history of the Japanese sword as a symbolic scene of an era when the blade was "the protagonist of the battlefield."