The Friendship That Doomed a Daimyō: Why Ōtani Joined Mitsunari Knowing They Would Lose

In July of Keichō 5 (1600), Ōtani Yoshitsugu, en route west to join the punitive expedition against Uesugi Kagekatsu, stopped at Sawayama Castle in Ōmi and met with Ishida Mitsunari. Mitsunari informed him of the planned uprising against Tokugawa Ieyasu and asked him to participate. The recorded conversation has been told ever since as one of the extreme cases of friendship-versus-judgment in the Sengoku period.

The Three Problems Ōtani Identified

Ōtani had a contemporary reputation as one of the few daimyō who combined military and administrative capacity at the top level. He was in a position to evaluate the gap between Ieyasu and Mitsunari calmly. He raised three problems with Mitsunari's plan. First, Mitsunari's own lack of personal following. Despite his recognized administrative talent, Mitsunari was deeply distrusted by the bunin-faction generals; in 1599 seven of them, including Fukushima Masanori and Katō Kiyomasa, had nearly killed him. Second, the strength of Ieyasu's political reach. He had been skillfully exploiting Toyotomi-house factionalism to draw daimyō into his orbit. Third, the lack of time. The moment the Western Army moved, Ieyasu would react, and there would be no opportunity for proper preparation.

Why He Joined Anyway

Having laid out the case against the uprising, Ōtani then agreed to join it. The motive was friendship. The two men had built one of the closest personal trusts in the Toyotomi house in Hideyoshi's lifetime, and Mitsunari had continued the same close relationship after Ōtani's skin disease had begun to alter his appearance. The famous anecdote of Mitsunari draining without hesitation the tea bowl into which Ōtani's lesions had bled is preserved as the emblem of that trust. Ōtani told Mitsunari clearly that his participation was not a strategic judgment but an act of righteousness.

Sekigahara Preparations

Having committed, Ōtani moved fast. He pushed forward from Tsuruga to the Sekigahara region and was in position at the northern foot of Matsuo Mountain by September 14. His tactical sense remained cold. He had identified Kobayakawa Hideaki on Matsuo Mountain as the principal risk and arranged his own line so that it could absorb Kobayakawa's defection if it came. On September 15, when Hideaki defected to the Eastern Army just past noon, the Ōtani line did absorb the first attack. What broke it was the simultaneous defection of Wakizaka Yasuharu and the other allied commanders. Ōtani committed suicide on the field.

What Survived His Death

Ōtani's decision has been told repeatedly in Edo-period literature and modern historical fiction as the standing extreme case of friendship and rectitude under combat conditions. The choice to throw one's life away for a cause one knows is unlikely to win, for the sake of a friend who needs help, made a strong impression on the warrior ethic that followed. The Ieyasu side recognized this too — the post-battle dispositions of Ōtani's retainers were unusually lenient. The friendship of Mitsunari and Ōtani at Sekigahara is preserved as one of the few moments in the Sengoku in which political success was not the only available value.

"I came for righteousness; I die for righteousness. There is nothing further to be said."