The men who gathered at Sawayama Castle on August 17, 1600 believed they were saving Japan. Ishida Mitsunari — former administrator of the Toyotomi regime, brilliant, meticulous, and widely disliked by the daimyo whose cooperation he now desperately needed — had spent weeks assembling the coalition that would stop Tokugawa Ieyasu from consolidating his grip on a country that still nominally belonged to the Toyotomi heir. Now, with three key allies seated around him — 大谷吉継 (Ōtani Yoshitsugu), 安国寺恵瓊 (Ankokuji Ekei), and 増田長盛 (Mashita Nagamori) — he had one final piece to place.

He needed a great name at the head of the enterprise. He needed 毛利輝元 (Mōri Terumoto).

Mori Terumoto was one of the five regent daimyo left by Toyotomi Hideyoshi to govern Japan after his death. His domain in western Japan was vast, his name was legendary, his army was enormous. The invitation was carried by Ankokuji Ekei — a Rinzai Buddhist monk in full clerical robes who also happened to be one of the most effective diplomatic operatives the Mori clan had ever produced. A monk helping plan what would become the last great samurai civil war of the era, persuading a feudal lord to stake his dynasty on a coalition against the most powerful man in Japan. Terumoto accepted. On August 22, he arrived at Osaka Castle and formally took command of the western alliance.

On paper, the assembly was formidable. A legendary name at the head, a brilliant strategist directing operations, tens of thousands of troops, and geographic control of western Japan. The planning meeting at Sawayama had all the structure of a heist: the strategist, the loyalist, the diplomat, the figurehead. Every piece fit. The audience watching knows the heist will fail because the getaway driver is already working for the other side.

吉川広家 (Kikkawa Hiroie), a senior Mori retainer, had already opened private communications with Tokugawa Ieyasu. The arrangement was simple: the Mori forces would not interfere. On October 21, 1600, at the Battle of Sekigahara, Hiroie made good on the promise. He positioned his troops directly behind the Mori contingent — physically blocking Mori Hidemoto from advancing. While Mitsunari's army fought and died three hundred yards away, the largest single contingent of the western alliance sat immobile. When asked why the Mori were not moving, Hiroie said he was busy eating his meal.

Ōtani Yoshitsugu had reportedly told Mitsunari before the campaign that the western side would lose. He was carried to the battlefield in a covered palanquin — afflicted with leprosy severe enough that he was nearly blind — and chose to fight anyway. Loyalty to his friend mattered more than survival. He was destroyed when Kobayakawa Hideaki's defecting forces slammed into his flank.

Mitsunari fled into the mountains. Ankokuji Ekei was captured and executed in Kyoto on November 6. Hiroie had been promised his domain would be preserved. Ieyasu seized most of the Mori lands anyway, citing letters suggesting Terumoto had been more complicit than claimed. The dōmei (同盟) — the coalition built on pledges — ended exactly as it deserved to end for a structure whose foundation had been rotten from the day the papers were signed.