Before dawn, 31,000 men crossed the 木曽川 (Kiso-gawa) in two columns and entered Mino Province. They moved in silence, or as close to it as 31,000 armed men can manage in the darkness. By the time the sky began to lighten, the Eastern vanguard was already pressing against the outer defenses of Gifu Castle's (Gifu-jō's) approaches.

The castle itself sat atop Mount Kinka, 329 meters above the city of Gifu below — a mountain fortress that generations of strategists had considered essentially impregnable. Not merely militarily strong: symbolically untouchable. These were the walls from which Oda Nobunaga had declared his ambition to rule all of Japan. He had renamed the city in 1567, borrowing the legendary Mount Qi (岐山, Gizan) of ancient Chinese mythology as a name fit for a world-historical enterprise. He had stamped his personal seal with the motto 天下布武 (tenka fubu) — 'spread military might under heaven' — a declaration that Japan would be unified by force, from this mountain, on his terms. Every stone of Gifu Castle was saturated with that ambition.

Oda Hidenobu was twenty years old. He was Nobunaga's grandson — son of Oda Nobutada, who had died alongside Nobunaga at the Honnoji Incident in 1582 when Hidenobu was not yet two years old. He had grown up entirely in the shadow of a legend he had never actually known, inheriting Gifu Castle and the impossible weight of the Oda name. When the coalitions formed ahead of Sekigahara, Hidenobu chose the Western side — the side of Ishida Mitsunari. It would prove to be the worst decision of his short life.

The Eastern vanguard had been moving fast. Column one, approximately 16,000 men under Fukushima Masanori, Ii Naomasa, and Honda Tadakatsu, advanced along the Tokaido road. Column two, approximately 15,000 men under Ikeda Terumasa and Asano Yoshinaga, moved along the river. Together they converged on Gifu like a closing hand.

Hidenobu's forces attempted to meet the eastern column in the field. His troops engaged Asano Yoshinaga's men near Zuiryuji temple (Zuiryuji) as the main assault developed. They were overwhelmed. The eastern forces moved with the momentum of an army that knew it was winning the campaign, not just the battle — men who had already heard what happened at Fushimi and understood that history was tipping.

By the following dawn, the castle had fallen. Approximately twenty-four hours, beginning to end. The mountain fortress that should have been impregnable had not held for even a single full day.

At Ogaki Castle (Ogaki-jō), thirty kilometers to the south, Ishida Mitsunari received the news. His outer defensive perimeter — the ring of castles and allied strongholds meant to slow the eastern advance — had collapsed at its most prestigious point. Gifu, the castle that carried Nobunaga's motto and his name, was gone. The psychological shock was not merely tactical. It was a signal: the Eastern Army could take anything. Their momentum was nearly unstoppable, their vanguard commanders moving with a speed that left no time for the Western coalition to consolidate.

Mitsunari's options were narrowing. He could not wait for his full western coalition to assemble — the eastern forces were already deep into Mino Province and moving. Within weeks, he would be forced to seek a decisive battle on ground not entirely of his choosing. The fall of Gifu was the moment the endgame began.

And the motto 天下布武 (tenka fubu) — 'spread military might under heaven' — had become an epitaph. The military might that spread across heaven in the autumn of 1600 belonged to someone else.