The most powerful warlord in Japan was killed on a summer night in 1582. 織田信長 (Oda Nobunaga) had spent decades pushing Japan toward unification, bending or breaking every lord who stood in his way. Then his own general, 明智光秀 (Akechi Mitsuhide), betrayed him at 本能寺 (Honnō-ji) temple in Kyoto — and with him died his heir, 信忠 (Nobutada). The most powerful domain in Japan was suddenly without a master.

The general who moved fastest was not the most senior. 羽柴秀吉 (Hashiba Hideyoshi), commanding an army far to the west and besieging 高松城 (Takamatsu-jō), received word of the 本能寺の変 (Honnō-ji no Hen — the Honnō-ji Incident) and acted with breathtaking speed. He negotiated an immediate ceasefire with the enemy he had been fighting — reportedly without telling them Nobunaga was dead — then force-marched his forces back toward Kyoto at a pace that left contemporaries astonished. On July 2, 1582, he met the traitor 明智光秀 (Akechi Mitsuhide) at 山崎 (Yamazaki) and destroyed him. Thirteen days after the betrayal, Nobunaga was avenged. No other general had even assembled a full response.

Then Hideyoshi walked into the conference room.

The 清洲会議 (Kiyosu Kaigi — Kiyosu Conference) was held on the 27th day of the 6th month of 天正 (Tenshō) 10 at 清洲城 (Kiyosu-jō), in what is now Aichi Prefecture. Four senior 織田 (Oda) vassals attended: Hideyoshi, 柴田勝家 (Shibata Katsuie), 丹羽長秀 (Niwa Nagahide), and 池田恒興 (Ikeda Tsuneoki). The question was succession.

Three candidates were put forward. 織田信雄 (Oda Nobukatsu), Nobunaga's second son, was an adult — but regarded as incompetent. 織田信孝 (Oda Nobutaka), the third son, was backed by 柴田勝家 (Shibata Katsuie), who had personally presided over his coming-of-age ceremony; Nobutaka was a capable adult, the strategically sensible choice for anyone who wanted Oda power to continue under Oda hands. Then there was 織田秀信 (Oda Hidenobu), nicknamed 三法師 (Samboshi) — Nobunaga's grandson through the slain 信忠 (Nobutada), barely three years old.

Hideyoshi championed the infant.

It was a masterstroke dressed as loyalty. By backing the direct bloodline — 信長 (Nobunaga)'s own grandson, child of the murdered heir — Hideyoshi appeared to be the most faithful man in the room. He was honoring succession, not gaming it. But a three-year-old cannot govern. A three-year-old needs a guardian. In nominating 三法師 (Samboshi), Hideyoshi was quietly nominating himself as the power behind the throne.

The conference voted for the child. Land redistribution followed, with outcomes that favored Hideyoshi's position considerably. 鬼柴田 (Oni Shibata — Demon Shibata) — the most feared military commander of the Oda retinue, veteran of decades of war — had been outmaneuvered without a single blow being struck.

Katsuie did not accept the outcome quietly. He backed 信孝 (Nobutaka) and formed an alliance against Hideyoshi. The confrontation came in spring 1583 at the 賤ヶ岳の戦い (Shizugatake no Tatakai — Battle of Shizugatake). Hideyoshi crushed Katsuie's forces. The old general retreated to 北ノ庄城 (Kitanosho-jō), and rather than surrender, burned it. He died inside — along with his wife 市 (Oichi), Nobunaga's own sister, already once widowed by war. She is remembered as one of the most tragic figures of the 戦国 (Sengoku) era: a woman twice handed to powerful men, twice consumed by their destruction. 信孝 (Nobutaka) was forced to commit 切腹 (seppuku) shortly after.

By late 1583, 羽柴秀吉 (Hashiba Hideyoshi) — the peasant's son, the Monkey, the man with no samurai lineage whatsoever — was the undisputed master of central Japan. He would later give himself a noble surname, 豊臣 (Toyotomi), and manufacture a fictional aristocratic ancestry to justify a position that needed no justification: he had simply won.

The 清洲会議 (Kiyosu Kaigi) is remembered as the meeting that made all of it possible. Not a battle. A conference. Four men, one infant's name, one calculation so precise it ended an era.