On January 3, 1868, the fifteen-year-old Emperor Meiji sat in the Kogosho — a small hall within the Kyoto Imperial Palace, originally designed for audiences with samurai envoys — and presided over the most consequential political act in Japanese history since a warrior named Minamoto no Yoritomo had established military rule nearly seven centuries earlier. With a single decree, the boy emperor abolished the shogunate, eliminated the offices of regent and imperial advisor, and established a new government under direct imperial authority. The decree had a name: 王政復古の大号令 (Ōsei Fukko no Daigōrei). The Restoration of Imperial Rule.

But the real action was the coup that made it possible. That morning, troops from Satsuma, Tosa, Aki, Owari, and Echizen had quietly seized the gates of the imperial palace, barring Tokugawa loyalists from entry. The timing was surgical: Tokugawa Yoshinobu, the last shogun, had already formally returned governing authority to the emperor back in November — a political gambit known as 大政奉還 (Taisei Hōkan). It had been a calculated move, not a surrender. The idea, originally proposed by the Tosa domain through the influence of 坂本龍馬 (Sakamoto Ryōma), was that Yoshinobu would step down as shogun but preside over a new council of lords — remaining, in practice, the most powerful man in Japan. The imperial court had no bureaucracy, no system for governing. Yoshinobu was betting that they couldn't run the country without him.

The decree of January 3rd called that bluff. It didn't just accept Yoshinobu's resignation; it stripped the Tokugawa of their lands, their offices, and their role in the new order entirely. What made this possible was a parallel move that almost nobody talks about: on the very same day Yoshinobu had submitted his resignation in November, Iwakura Tomomi — the cunning court noble orchestrating the anti-Tokugawa faction — had secretly obtained an imperial order authorizing the use of force against the shogunate. Whether Yoshinobu cooperated or not, the Satsuma-Chōshū alliance had been preparing for war.

That evening, in what became known as the Kogosho Conference, the assembled lords debated Yoshinobu's fate. The former Tosa lord Yamanouchi Yōdō, sympathetic to the Tokugawa, argued for moderation and reportedly wept. Iwakura held firm. And outside the hall, 西郷隆盛 (Saigō Takamori) — the Satsuma leader who had positioned his troops around the palace — was said to have remarked during a recess that the whole discussion could be settled with a single short sword. The decision stood: Yoshinobu must surrender his lands and resign all titles.

For a brief moment, it looked like moderation might still win. Yoshinobu calmly withdrew from Kyoto to Osaka Castle rather than fight, and the moderate faction in the new government temporarily gained the upper hand — even discussing allowing Yoshinobu a seat in the new cabinet. But Saigō had a backup plan. He dispatched agents to Edo to commit arson, looting, and violence designed to provoke a Tokugawa response. It worked. The Shōnai domain, responsible for security in Edo, burned the Satsuma residence to the ground. When news reached Osaka, Yoshinobu's enraged loyalists demanded war. Unable to restrain them, he authorized them to march on Kyoto.

They were met at the southern approaches to the city by roughly 5,000 imperial troops armed with modern rifles and artillery, dug into positions around Toba and Fushimi. The Tokugawa force numbered around 15,000 — but many were still armed with pikes and swords. On the second day of fighting, the imperial brocade banner appeared behind the Satsuma-Chōshū lines. Any soldier who continued fighting was now, officially, an enemy of the emperor. Domain after domain defected. Yoshinobu fled Osaka by warship.

The samurai class had just been told its time was up. Not everyone planned to go quietly.