What was the Battle of Nagashino?
At Nagashino, the combined armies of Oda Nobunaga and Tokugawa Ieyasu destroyed the field army of Takeda Katsuyori in a single day, killing a large part of the Takeda senior command.
It is the battle most often described as the moment firearms changed Japanese warfare. That description is not wrong, but the specific story most people know — three thousand gunners firing in three rotating ranks — is considerably less certain than its fame suggests.
Why did it happen?
Katsuyori had been pressing into Mikawa and Totomi since inheriting the Takeda in 1573. In 1575 he besieged Nagashino Castle, a small Tokugawa fortress covering the route into Mikawa.
The garrison held. A messenger, Torii Sune'emon, slipped out to bring word that relief was coming, was captured on his return, and — by the well-known account — shouted the news to the defenders instead of the surrender demand he had been ordered to deliver, and was executed for it.
The relief army arrived with roughly three times Katsuyori's numbers. He chose to fight it rather than withdraw.
Forces and sides
The allied army is usually given as around 38,000, the Takeda as around 15,000. The disparity is not seriously disputed.
The number of arquebuses is disputed. The figure of 3,000 comes from later editions and copies of the Shincho Koki and from Edo-period works; some early manuscript versions give 1,000. Modern estimates range widely. The number that matters may be less the total than the fact that they were sited behind palisades on ground the Takeda had to cross.
What happened?
Nobunaga chose a position behind the Rengogawa stream, on rising ground, and built wooden palisades along the front with gaps for counterattacks. A detachment was sent overnight to take the Takeda siege position at Tobigasuyama, behind the Takeda army, which it did at dawn.
The Takeda attacked across marshy ground in successive waves. Each wave had to cross the stream and reach the palisades under fire. The fighting lasted most of the morning.
By the time Katsuyori withdrew, the Takeda had lost an enormous proportion of their senior officers — Baba Nobuharu, Yamagata Masakage, Naito Masatoyo, Sanada Nobutsuna and Masateru among them. These were men who had built the army under Takeda Shingen.
Turning point
The loss of Tobigasuyama at dawn meant the Takeda could not simply break off the siege and withdraw in good order; their line of retreat was threatened, which pushed Katsuyori towards a frontal commitment.
After that, the palisades did the work. Cavalry and infantry attacking uphill across a stream into a prepared line take losses regardless of what weapons the defenders are holding.
Outcome
Katsuyori escaped with a fraction of his army. The Takeda continued to fight for seven more years but never recovered the command depth lost in one morning, and the house was destroyed in 1582.
For Nobunaga, Nagashino removed the last serious military threat from the east and let him turn his attention west and north.
Why it mattered
Nagashino is a genuine landmark in the use of massed firearms — but the more careful reading is that it was a victory of preparation, position and numbers, in which guns were one component. Rotating volley fire in three ranks is not described in the earliest sources and is now widely doubted by specialists.
The battle also demonstrates the deeper Oda advantage: Nobunaga could afford large quantities of guns, powder and lead, and could keep infantry in the field year-round. That was an economic difference before it was a tactical one.
The famous screen paintings of Nagashino were made long after the battle and reflect Edo-period ideas about it. They are illustrations of a story, not evidence for it.
