The Battle of Mikatagahara, on 25 January 1573, was a pivotal conflict during Japan's Sengoku period between Takeda Shingen and Tokugawa Ieyasu in Tōtōmi Province. Shingen's campaign aimed at challenging Oda Nobunaga and advancing towards Kyoto, targeted Ieyasu's position at Hamamatsu. Despite being heavily outnumbered, Ieyasu faced Shingen's 30,000-strong army with his 11,000 men. The battle saw Takeda forces employing the gyorin (fish-scale) formation, overwhelming Ieyasu's line with a series of cavalry charges, leading to a significant defeat for the Tokugawa-Oda forces.

Prior to the battle, Shingen had secured alliances and captured strategic locations, setting the stage for his southward push. Ieyasu, against the counsel of his advisors and allies, chose to confront Shingen at Mikatagahara. The battle commenced with Tokugawa forces initially resisting Takeda's attacks, but eventually, Takeda's tactical superiority and numerical advantage led to the near-annihilation of Ieyasu's forces, compelling a disorderly retreat.

Despite the defeat, Ieyasu's strategic withdrawal and subsequent counterattacks, including a daring night raid on the Takeda camp, sowed confusion among the Takeda ranks, forcing Shingen to reconsider his advance. Hattori Hanzō's exploits during this battle further delayed Takeda forces.

The aftermath of Mikatagahara highlighted the resilience of Ieyasu and his forces, despite the severe defeat. Shingen's campaign was halted by his injury and subsequent death in May 1573, preventing any further immediate threats to Tokugawa territories. The battle remains a significant illustration of Sengoku period warfare, demonstrating the use of cavalry tactics and the impact of strategic retreats and counterattacks.