The battle at Sekigahara lasted a few hours on the foggy morning of October 21, 1600. What Tokugawa Ieyasu did with the five days that followed shaped Japan for more than two and a half centuries.

Ieyasu moved immediately. He had planned for this: not just the battle, but what would come after, how the land would be redistributed, who would be placed where and why. The redistribution of Japan was not an afterthought — it was the point. Sekigahara was the mechanism. The apportionment of domains was the result.

And he did it verbally. No written letters of intent, no formal documents with seals and dates. He spoke his decisions directly, delivered through trusted messengers where necessary. Sources who recorded the aftermath noted this explicitly: the redistribution was conducted by spoken word. In a legal and political culture where written documents constituted authority, Ieyasu was reminding every daimyo in Japan that his word had become the document. His voice was the law.

Approximately 88 to 93 daimyo on the losing side lost their domains entirely — kaieki (改易), the stripping of rank. About 6.3 million koku worth of territory was confiscated. Roughly one-third of Japan's total agricultural production changed hands in the weeks following a single battle.

The winners received accordingly. Fukushima Masanori, a former Toyotomi loyalist who had switched to Ieyasu before the battle, went from 290,000 to approximately 498,000 koku, given domains in what is now Hiroshima Prefecture. Kuroda Nagamasa, another Toyotomi man who had crossed over, went from 180,000 to 520,000, placed in Chikuzen in Kyushu. Yamanouchi Kazutoyo made the most dramatic leap: from 50,000 to 200,000 koku, installed as lord of Tosa Province on Shikoku — a four-fold increase. His domain there would eventually produce revolutionary figures central to the Meiji Restoration of 1868, the chain of consequence running 268 years from this moment.

Then there was Kobayakawa Hideaki.

Hideaki was 22 years old at Sekigahara. He had arrived on the Western Army's side and sat on the Matsuo-yama ridge for most of the morning, watching the battle below, receiving increasingly urgent messages from both sides. The Western Army's generals — particularly Ōtani Yoshitsugu — had anticipated his wavering and positioned troops facing the Kobayakawa position. When Ieyasu's gunners finally fired warning shots at Hideaki's lines, he moved. He crashed down into Ōtani's flank, and four other Western divisions defected almost simultaneously. The Western Army collapsed in minutes.

For this, Hideaki received Okayama Castle and a domain assessed at somewhere between 400,000 and 520,000 koku — sources vary, but all agree it was enormous, placing him among the top tier of post-Sekigahara winners.

Ōtani Yoshitsugu, who had fought on the Western Army's side and whom Hideaki had betrayed, had arrived at Sekigahara in a covered palanquin. He had leprosy — likely Hansen's disease — so advanced that contemporary accounts describe him as barely recognizable. He was nearly blind and could not walk. He had already anticipated Kobayakawa's betrayal when he positioned half his troops facing the ridge. When Hideaki came down and four other divisions followed, Ōtani fought from his palanquin until the position collapsed. He asked his retainer Yuasa Gosuke to behead him — to prevent the head from being taken as a trophy — and Gosuke did, then committed seppuku himself. Ōtani received no domain, no castle, no reward. He received a legend.

Kobayakawa Hideaki received everything and held it for two years. By December 1, 1602, he was dead at 25, without heirs, the Kobayakawa clan extinct alongside him. The most historically supported explanation is acute organ failure from chronic heavy drinking. But the folk explanation has persisted for four centuries: the ghost of Ōtani Yoshitsugu drove him mad.

The strategic architecture of the redistribution was as important as the specific koku figures. Ieyasu kept the most strategically vital territories for himself and his fudai (譜代) — hereditary vassals who had served the Tokugawa before Sekigahara. The roads into Edo, the passes through the mountains, the ports on the Sea of Japan and the Pacific coast: all placed in trusted hands. The tozama (外様) — outside lords, former enemies who had come over or been defeated — were pushed to western Japan. They were well-compensated in many cases, but they were surrounded by Tokugawa vassals at every strategic point, their movements watched, their access to Edo and Kyoto controlled.

Mōri Terumoto had been the nominal commander of the Western Army, though he had stayed in Osaka Castle and never personally fought at Sekigahara. He survived — Kikkawa Hiroie, one of his own vassals, had secretly brokered a deal with Ieyasu before the battle — but the price was everything. Eight provinces reduced to two: Suō and Nagato, the western tip of Honshu, far from anywhere that mattered. From over 1.2 million koku to approximately 300,000. The domain that survived would eventually become Choshu, one of the domains that would destroy the Tokugawa shogunate 268 years later. They did not forget.

Uesugi Kagekatsu, whose defiant refusal to answer Ieyasu's summons in summer 1600 had been the immediate trigger for the Sekigahara campaign, went from his massive Aizu domain — 1.2 million koku — to Yonezawa in the northeastern mountains, 300,000 koku. Distant, reduced, and watched.

Konishi Yukinaga, Ishida Mitsunari, and the monk Ankokuji Ekei — the three most prominent Western Army leaders captured after the battle — received nothing but death. They were executed in Kyoto on November 6, 1600, beheaded at the dry Kamo riverbed, their heads displayed at Sanjō Bridge. Mitsunari had been one of Hideyoshi's closest administrators and the architect of the Western coalition against Ieyasu. He died reportedly calm, asking for a persimmon at his last meal and, when told they were bad for the digestion before death, noting that his digestion was not going to be a concern much longer.

Ieyasu would be named shogun by the emperor in 1603 — three years after Sekigahara, following the formal precedent. He handed the position to his son Hidetada in 1605 to establish the dynastic principle, then watched the Toyotomi remnants in Osaka Castle for another decade. By 1614, it was the bell that gave him his excuse. By 1615, the castle had fallen. The map Ieyasu drew in the days after Sekigahara had made the outcome inevitable from the start.