The Kōzanji Coup: How Eighty Men Turned a Domain to Rebellion in One Night

On the night of December 15, 1864 (the seventeenth of the eleventh month of Genji 1), Takasugi Shinsaku raised arms at the Sōtō Zen temple Kōzanji in Shimonoseki. The men with him — including Itō Hirobumi and a few others — numbered just over eighty. Against the regular Chōshū army, the conservative faction now in control of the domain government, and the bakufu coalition pressing in from outside, Takasugi launched what was effectively an internal coup against his own domain's government.

The Run-Up

After the Kinmon Incident in July 1864 the Chōshū domain had been declared an enemy of the Court, and the bakufu had ordered the First Chōshū Expedition. Inside the domain the conservative Mukuri Tōta faction had seized the government and was steering it toward submission — reparation to the bakufu and execution of the sonnō-jōi leadership. Kusaka Genzui and other Kiheitai-aligned leaders were being killed; Takasugi himself was in hiding. The domain's political line had hardened into bakufu accommodation, and Chōshū was on the verge of dropping out of the anti-bakufu coalition.

Eighty-Odd Men

On the night of the fifteenth, Takasugi delivered the uprising speech at Kōzanji. The surviving accounts are brief — the gist was that the five Court nobles in refuge in Shimonoseki, beginning with Sanjō Sanetomi, would be the rallying figures, and that the domain government would be returned to the anti-bakufu line. That same night the eighty stormed the Shimonoseki municipal warehouse for arms and ammunition, and then took three Chōshū naval vessels at Mitajiri. Through January and into March 1865 they fought across Isaki and Ōta-Egō and broke the conservative-faction main force; by March the domain government was back in their hands.

Three Months That Turned the Domain

By April 1865 a new Chōshū government under Takasugi, Katsura Kogorō (later Kido Takayoshi) and others had been installed, and the domain line was again anti-bakufu. From the Kōzanji uprising to that consolidation took roughly three months. Despite still being under designation as an enemy of the Court, Chōshū resumed preparations to bring down the bakufu. Without that turn, the rout of the bakufu army in the Four-Border War the following year would not have happened, and the Satsuma-Chōshū Alliance of 1867 would not have been possible. Late-Bakumatsu historiography returns repeatedly to the verdict that the Meiji Restoration began on the night at Kōzanji.

"What must be done today, we will do."