Battle of Anegawa

What Happened

On 30 July 1570, two allied armies met the combined forces of two rival clans on the floodplain of the Anegawa, a river flowing into Lake Biwa in Ōmi Province, in the centre of the Japanese main island of Honshu. The alliance was led by Oda Nobunaga, the rising warlord who had entered the capital, Kyoto, two years earlier, and Tokugawa Ieyasu, the lord of Mikawa Province to the east. Their opponents were the Azai clan under Azai Nagamasa and the Asakura clan under Asakura Yoshikage.

The battle is remembered for the ferocity of its close-quarters fighting and for Nobunaga's heavy reliance on firearms. Matchlock guns, introduced to Japan by Portuguese traders in 1543 and by 1570 manufactured in large numbers domestically, were deployed in organised volleys against the Azai and Asakura lines. The fighting lasted through the day; the Oda and Tokugawa forces broke the Azai and Asakura formations and the defeated armies withdrew toward their home castles to the north.

Background

Through the 1560s Oda Nobunaga had expanded from his base in Owari Province toward Kyoto, and in 1568 he installed Ashikaga Yoshiaki as shogun, giving his military power a nominal legitimacy. Nobunaga's eastern flank was guarded by his ally Tokugawa Ieyasu, whose territory bordered the lands of the Azai and Asakura clans. The two clans were linked by marriage: Azai Nagamasa had married Nobunaga's younger sister, Oichi, in 1567, an alliance that was meant to secure Nobunaga's northern border.

In 1570 Nobunaga marched north against the Asakura stronghold of Kanegasaki. Azai Nagamasa, bound by an older and more binding alliance to the Asakura, broke with Nobunaga and attacked the Oda army's rear as it withdrew, forcing a costly retreat. The betrayal turned the Azai into a primary target. Nobunaga regrouped, brought Ieyasu's forces west, and in the summer of 1570 advanced again into Ōmi. The two sides met at the Anegawa on 30 July.

Why It Mattered

Anegawa was the first battle fought jointly by Oda Nobunaga and Tokugawa Ieyasu. Their alliance, which would hold for more than two decades and end with Ieyasu's establishment of the Tokugawa shogunate in 1603, was tested here and proved effective. The victory removed the immediate threat to Nobunaga's northern approaches to Kyoto and pushed the Azai and Asakura back onto the defensive.

The battle also demonstrated the battlefield value of massed firearms in the hands of a disciplined, centrally commanded force. Nobunaga would refine this approach further, most famously at Nagashino in 1575. Anegawa did not destroy the Azai or the Asakura; both clans survived until 1573, when Nobunaga took their castles and ended their power. But the campaign that began at the Anegawa set the pattern for the unification wars of the following decade.

The Name in Japanese

The Japanese name is 姉川の戦い, read in kana as あねがわのたたかい, and romanised as Anegawa no Tatakai.

Breaking it down:

• 姉 — read here as ane. The character means "elder sister". It is the first element of the river's name.
• 川 — read here as gawa, a voiced form of kawa. It means "river". Together, 姉川 (Anegawa) is the name of the river where the battle was fought.
• の — read no. This is the possessive and linking particle, equivalent to English "of" or the apostrophe-s. It joins the river name to the noun that follows.
• 戦 — read here as tatakai. It means "battle" or "war". The same character appears in 戦国 (Sengoku), the name of the era of civil war in which this battle took place.
• い — read i. This is the kana ending of the verb-derived noun tatakai, from the verb 戦う (tatakau), "to fight".

So the whole name means, literally, "the Battle of the Anegawa". The river itself, 姉川, is named "elder-sister river", a name of uncertain origin that long predates the battle.

Key Figures

Oda Nobunaga (織田信長) commanded the allied army. By 1570 he was the dominant military figure in central Japan and had placed a shogun in Kyoto. His use of firearms at Anegawa was a hallmark of his campaigns.

Tokugawa Ieyasu (徳川家康) brought his Mikawa forces to fight alongside Nobunaga. Anegawa was the first battle in which the two men fought as allies, and the alliance would define the next thirty years of Japanese politics.

Azai Nagamasa (浅井長政) led the Azai clan of northern Ōmi. He had married Nobunaga's sister Oichi, but chose his clan's older alliance with the Asakura over his marriage tie, and faced Nobunaga at Anegawa as an enemy.

Asakura Yoshikage (朝倉義景) led the Asakura clan of Echizen Province. His conflict with Nobunaga had drawn the Oda army north in 1570 and set the conditions for the battle.

Several warriors who fought at Anegawa later became prominent. Honda Tadakatsu (本多忠勝), a Tokugawa retainer, and Ikeda Tsuneoki (池田恒興), an Oda commander, were among those present. Takenaka Shigeharu (竹中重治), Hachisuka Masakatsu (蜂須賀正勝), and Gamō Ujisato (蒲生氏郷) are also recorded among the participants.