Most commanders, the morning after a battle, count their dead. Oda Nobunaga was already planning the next siege.

The Ane River plain on July 31, 1570 was the aftermath of victory: roughly 2,500 men dead or badly wounded across a wide stretch of shallow water and summer-baked bank, the heat doing its work, horses and broken spears scattered across the ground where the melee had been thickest. In the mountains to the north, Azai Nagamasa had reached Odani Castle (小谷城) (Odani-jō) intact. His family, his retainers, his military organization — all of it had retreated into the mountain fortress above the valley without decisive damage. To the east, the Asakura had pulled back across the mountains toward Echizen Province.

Nobunaga had won the field. He could see, with the cold clarity that distinguished him from nearly every other commander of his age, that he had not yet won anything that mattered.

Ten years earlier, at the Battle of Okehazama (桶狭間の戦い) (Okehazama no Tatakai), Nobunaga had attacked Imagawa Yoshimoto's massive army of perhaps 25,000 men in the middle of a thunderstorm with a fraction of that force. He had killed Yoshimoto himself in the chaos — and the entire enemy army had dissolved overnight. The general was dead; the war ended in hours. It had perhaps given Nobunaga an unrealistic model of how wars end.

Odani Castle sat atop a mountain. It could not be rushed, could not be flanked, could not be taken by the kind of bold stroke that had made Nobunaga famous. And the Asakura would not simply evaporate because they had lost a river battle — as he would discover in September, when a large Asakura relief force returned and he was forced to negotiate a ceasefire while simultaneously dealing with the Ikko-ikki (一向一揆) (Ikkō-ikki) Buddhist uprising erupting to his west. The "decisive" victory of July 30 was followed immediately by the worst strategic crisis of his career.

But before any of that unfolded, on the morning of July 31, Nobunaga issued the order that revealed how his mind worked: begin construction of Yokoyama Castle (横山城) (Yokoyama-jō). A new fortification, not a captured one, positioned in Ōmi Province (近江国) (Ōmi no kuni) to serve as a permanent forward base — close enough to watch Odani's supply routes, positioned to prevent Asakura reinforcement from the mountain passes, a brick in the long wall of a long siege.

Nobunaga was known for fast construction. Azuchi Castle (安土城) (Azuchi-jō), built a few years later, would stun observers with its speed and scale. He understood that the ability to build quickly was itself a weapon — a fortified position changed the geography of a war before the enemy could respond.

The 後始末 (atoshimatsu) — the handling of what comes after, the reckoning with aftermath — was completed before the burial details had finished their work. That was Nobunaga: not a man who savored the battle, but a man already standing in the future the battle had made possible.

Three years later, in 1573, Odani Castle fell. The machinery built in those three years — the supply chains, the siege fortifications, the coalition management — was forged in the uncomfortable truth of July 31, 1570: winning is not the same as winning.