Kinmon Incident (Hamaguri Gomon Incident)

The Kinmon Incident of August 20, 1864 — named for the kinmon (forbidden gates) of the Imperial Palace — was the most violent street battle of the Bakumatsu period and the event that definitively designated Chōshū domain as an imperial enemy, setting in motion a chain of consequences that would culminate in the Meiji Restoration four years later.

The background lay in the political revolution of August 1863, when a coalition of Satsuma and Aizu domains — supported by the shogunate — had expelled Chōshū's forces and influence from Kyoto in the coup known as the "August 18th Political Change." The Chōshū loyalist activists who had dominated radical politics in the capital were driven out; seven sympathetic court nobles accompanied them into exile. Chōshū's political position went from dominant to precarious overnight.

What the August 1863 coup could not do was eliminate Chōshū's military capacity. The domain continued to recruit, arm, and train; radical activists continued to plan a return to Kyoto that would restore Chōshū's position and vindicate their cause. In July 1864, just days before the Kinmon Incident, the Ikedaya Incident had already shown how volatile the situation had become: the Shinsengumi's raid on the Ikedaya inn killed or captured dozens of Chōshū-affiliated activists who had been planning to set fire to Kyoto and assassinate pro-shogunate officials.

The Kinmon assault was partially a response to the Ikedaya massacre and partially the planned strategic offensive that had been in preparation for months. On the morning of August 20th, approximately two thousand Chōshū troops moved on the Imperial Palace from several directions, attempting to seize the gates and present a fait accompli to the court: with Chōshū soldiers controlling access to the emperor, the domain could negotiate from strength and demand the reversal of its outlawed status.

The fighting at Hamaguri-gomon Gate (the Clam Gate, so called because it had remained sealed for so long that its hinges had rusted shut — until the extraordinary event of this assault forced it open, like a clam in the heat) was intense. Kijima Matabei, leading Chōshū cavalry in a frontal assault, was killed by rifle fire. Kusaka Genzui — one of Chōshū's most brilliant young activists, a disciple of the executed Yoshida Shōin — maneuvered into the Takatsukasa mansion and attempted to negotiate; cornered, he committed suicide at age twenty-five. The defense, organized by Satsuma troops under Saigō Takamori and Aizu troops under Matsudaira Katamori, held firm.

As the Chōshū forces retreated in disorder, fires broke out across the city. Whether the arson was deliberate policy, the act of desperate individual fighters, or accidental in the confusion of combat remains disputed, but the result was not: the "Dondonyaki" (roughly "the great burning") consumed roughly a quarter of Kyoto's built area. Tens of thousands of buildings burned; tens of thousands of residents were displaced. The fires are remembered in Kyoto to this day as one of the great disasters in the city's history.

The sword culture implications of the Great Dondonyaki Fire were significant. Kyoto had been, since the Heian period, one of the primary centers of Japanese sword culture — home to sword polishers (togishi), appraisers (kantei-ka), dealers, and patrons whose collections represented centuries of accumulated expertise and cultural value. The fires destroyed an unknown number of significant blades along with the rest of the city's material heritage. The precise losses are impossible to quantify; the records that might have documented them were themselves burned. But the destruction was real.

The battle itself exemplified the military transition of the Bakumatsu period. The Chōshū forces used a combination of matchlock rifles and swords; the defenders combined rifle volleys with close-quarters fighting. Kijima Matabei's death by rifle fire — charging on horseback with the traditional courage of a mounted warrior into an era that had moved past such tactics — was emblematic of the period's contradictions: men trained in the old martial traditions fighting with, and against, modern firearms.

The Shinsengumi, which had conducted the Ikedaya raid just days before, participated in the suppression of the Kinmon Incident as well. Their commander Kondō Isami and vice-commander Hijikata Toshizō — both accomplished swordsmen of the Tennen Rishinryū style — were present in Kyoto throughout this period. The Shinsengumi's role in the Bakumatsu tumult — as enforcers of shogunal order against the sword-wielding activists of Chōshū and its allies — made them the most famous practitioners of classical Japanese swordsmanship in the final years before the Meiji Restoration rendered that tradition obsolete.

The political aftermath was swift. Chōshū was formally designated an imperial enemy; the First Chōshū Expedition assembled shogunate forces to compel submission. But Chōshū refused to collapse; under Takasugi Shinsaku's leadership, the domain organized the Kiheitai — mixed units of commoners and samurai, armed with modern rifles — and prepared for a very different kind of war. By 1866, Chōshū and Satsuma had formed their secret alliance; by 1867, the shogunate had collapsed; by 1869, the last Tokugawa resistance at Hakodate had ended. The flames of the Kinmon Incident were, in retrospect, the beginning of the final configuration.