Hamamatsu Castle

Tokugawa Ieyasu relocates his primary base from Okazaki Castle to Hamamatsu, reflecting his expanding control westward into Totomi Province. He begins substantial construction on the existing fortification on the plateau, making it his main castle for the next 17 years.

Takeda Shingen leads a massive invasion force west through Totomi Province — the 'Nishigari' ('Western Hunt') campaign — threatening to push through to Kyoto. Ieyasu, with Oda Nobunaga's support, prepares to meet him.

The Battle of Mikatagahara: Ieyasu leads his forces out of Hamamatsu to intercept Takeda Shingen's army in the open field. The result is a catastrophic defeat — Ieyasu's army is routed and he barely escapes back to Hamamatsu Castle. According to legend, he was so frightened during the retreat that he soiled himself. He ordered a portrait painted of himself in his terrified state — the 'Kaname Portrait' — and kept it to remind himself never to be complacent. Shingen does not press the siege, and dies of illness weeks later.

The Battle of Nagashino: Ieyasu and Nobunaga together destroy Takeda Katsuyori's army with arquebus tactics. The threat to Hamamatsu from the east is permanently ended. Ieyasu begins consolidating his hold on all of Totomi Province.

Tokugawa Ieyasu relocates his headquarters to Sunpu (modern Shizuoka), leaving Hamamatsu Castle to his retainer Horii Tokiharu. Ieyasu's 17 years at Hamamatsu — including his worst military defeat and his greatest victories — are over.

A three-story concrete tenshu is reconstructed on the original Honmaru site, becoming the focal structure of Hamamatsu Castle Park. The reconstruction, based on records that may not accurately reflect the original tower's dimensions, gives the park its visual anchor if not its historical authenticity.