Kioizaka Incident

The Kioizaka Incident (Kioizaka no hen) took place on May 14, Meiji 11 (1878), in Shimizutani, Kioizaka-chō, Kojimachi Ward, Tokyo (present-day Chiyoda Ward, Kioizaka-chō), when Okubo Toshimichi, Minister of Home Affairs, was assassinated by six samurai from Ishikawa and Shimane prefectures. Okubo received 16 wounds across his entire body, including to his head, from a katana and died instantly. He was 49 years old. The katana used by the ringleader, Shimada Ichirō, was confiscated and preserved by the Metropolitan Police Department, where it remains housed in their Special Archives Room today. This incident occurred two years after the Sword Abolition Edict (Meiji 9, 1876) was enacted, and represents the most shocking example of former samurai employing the katana as a means of political violence after the abolition, making it a particularly noteworthy event in both Meiji and sword history.

Okubo Toshimichi and the Power Structure of the Meiji Government

Okubo Toshimichi (1830–1878) was a founding father of the Meiji Restoration from Satsuma domain and one of the most powerful figures of early Meiji, having led the abolition of domains and establishment of prefectures (1871), the Iwakura Mission (1871–1873), the land tax reform (1873), and the suppression of the Satsuma Rebellion (1877). He established the Ministry of Home Affairs and became its first minister, constructing the centralized administrative apparatus of the modern nation-state. Although Okubo is counted among the "Three Great Meiji Restorers" alongside Saigō Takamori and Kido Takayoshi, during the Satsuma Rebellion (1877) he made the anguishing decision to suppress his longtime ally Saigō Takamori with government forces. This decision brought Okubo profound pain; after the rebellion's end, he reportedly told a friend, "If I can live three more years, I can accomplish my work"—a wish that would never be fulfilled. After the Satsuma Rebellion, Okubo faced dual political pressure: the rising Popular Rights Movement led by Itagaki Taisuke and Gotō Shōjirō (who had left government over the Korean dispute of 1873), and the discontent of the former samurai class.

The Assassination and the Katana Attack

Around 8:30 a.m. on May 14, Meiji 11, Okubo Toshimichi was traveling by carriage toward the temporary imperial palace at Akasaka (near present-day Akasaka Imperial Residence) when he reached the slope at Shimizutani, Kioizaka-chō (present-day Kioizaka slope). Six samurai—Shimada Ichirō, Chō Rengo, Sugimoto Otokiku, and Wakita Kōichi from Ishikawa prefecture, and Asai Toshiatsumi from Shimane prefecture—who had been lying in wait above the slope suddenly surrounded and attacked the carriage. They first slashed the horses to stop the carriage, then killed the coachman Nakamura Tarō before opening the carriage door and striking at Okubo. Okubo Toshimichi received 16 wounds across his entire body, including to his head, from the katana and died instantly. The six assassins surrendered immediately after the attack and were all executed by beheading for treason on July 27 of the same year. Okubo's body was returned to his residence the same day, and news of his death sent shockwaves through the entire Meiji government.

The Blades Used and Their Preservation by the Metropolitan Police

The katana used by the ringleader Shimada Ichirō was confiscated by the Metropolitan Police as evidence following the incident. This blade remains preserved today in the Special Archives Room within the Metropolitan Police Headquarters, possessing extremely high historical and archival value as a katana actually used in a Meiji-era political assassination. It is believed that the perpetrators, including Shimada Ichirō, had hidden their swords even after the Sword Abolition Edict (1876) took effect. The edict prohibited public sword-wearing but did not completely forbid sword possession or storage in private homes; in practice, former samurai keeping swords in their residences was tacitly permitted. The blades used by the perpetrators were likely practical combat katana from the shin-shintō period (Kansei to Bakumatsu, 1789–1868). The shin-shintō represented studies and revival of old and new sword techniques by late-Edo craftsmen, characterized by a style emphasizing practical cutting ability and durability. The specific signature of the blade used in the assassination is not recorded in historical sources, but the katana preserved at the Metropolitan Police serves as a unique and irreplaceable artifact testifying to an era when the post-abolition katana still functioned as a "weapon." This blade provides singular evidence that in the years between the Sword Abolition Edict and the establishment of the Japan Sword and Martial Arts Museum (NBTHK) in Showa 23 (1948)—approximately 70 years—countless shin-shintō blades of the same period were preserved as artworks despite upheaval and modernization.

The Perpetrators' Motivation and the "Zankanjō"

Before the assassination, the perpetrators drafted a "zankanjō" (statement justifying the slaying)—a document explaining their reasons for killing Okubo—enumerating four grievances. The main accusations in this statement were: "He dismissed imperial authority and ruled despotically," "He caused suffering to the people through wicked policies including the land tax reform and suppression of the Satsuma Rebellion," "He suppressed civil rights," and "He failed to handle the Korean question favorably." This indictment encapsulates the structural contradictions of early Meiji—the Korean dispute, the Popular Rights Movement, and the economic hardship of former samurai—transcending personal grievance to become an eruption of historical structural contradictions. The Okubo assassination can be interpreted as the dying gasp of the former samurai class—now stripped of their privileged status, stipends, and the right to bear swords through policies including abolition of domains, the Sword Abolition Edict, and the commutation of samurai stipends—manifesting as the final glimmer of the katana.

The Post-Abolition Katana—The Last Brilliance of a Forbidden Weapon

The Kioizaka Incident occurred merely two years after the Sword Abolition Edict (1876) took effect. The edict prohibited all sword-wearing except "when wearing court dress for state ceremonies and when military personnel or police officers carried swords in the line of duty"—an epochal law. Yet shortly afterward, in October Meiji 9, the Shinpuren Rebellion erupted in Kumamoto, and in October 1876, the Hagi Rebellion broke out, with former samurai in both cases taking up swords and rifles against the Meiji government. The following year, in Meiji 10 (1877), the Satsuma Rebellion saw samurai forces led by Saigō Takamori challenge the government, ultimately defeated by the government's modern equipment and conscript army. The Kioizaka Incident occurred the year after the Satsuma Rebellion's conclusion, marking one of the last major public events in which the post-abolition katana was employed—not as an instrument of armed rebellion but as a tool of political assassination. After this incident, the opportunities for the katana to appear as a primary instrument of political violence in public incidents rapidly diminished. The sword transitioned completely from practical war-weapon to art object and symbol of spiritual culture, beginning the long transformation that led to today's sword culture.

Shin-Shintō and Meiji-Era Swordsmiths—Sword Culture on the Eve of Abolition

Meiji 11 (1878), when the Kioizaka Incident occurred, was immediately after the Sword Abolition Edict (1876), a period of significant social change in sword production, circulation, and possession. Before the edict, during the shin-shintō period (Kansei to Keiō, 1789–1868), master craftsmen including Minamoto Kiyomaro, Katayama Sōji, Yamaura Masao, Yamaura Kiyomaro, and Gassan Sadaichi left masterpieces. Even after the abolition edict, swordsmiths continued their craft, but with the loss of practical military demand, production shifted toward art blades, ceremonial swords, and military swords for officers. Meiji-era swordsmiths including Gassan Sadaichi (second generation), Miyairi Yukihira, and Kurihara Hikozaburō Akihide established sword production as fine art and craft in the post-abolition era. The Kioizaka Incident is positioned as the event that most dramatically illustrates this transition "from sword as weapon" to "sword as art and craft." The very fact that the blade used in the assassination was preserved by the Metropolitan Police as "evidence" demonstrates that swords were already being incorporated into modern value systems where they were treated as objects of "management and preservation."

Historical Aftermath—Meiji Politics After Okubo's Death and Sword Culture

Okubo Toshimichi's death dealt a serious blow to the Meiji government. The vacuum left by the powerful political leadership Okubo had provided prompted the rise of Itō Hirobumi, Inoue Kaoru, and Yamagata Aritomo, transforming the power structure of the Meiji government. Okubo's unresolved political challenge—confrontation with the Popular Rights Movement—eventually found partial resolution through the Imperial Rescript on the Establishment of a National Assembly (1881) and the Meiji Constitution (1889). From the perspective of sword history, after the Kioizaka Incident, the enforcement of the Sword Abolition Edict was strengthened, and the possibility of former samurai employing the katana as an instrument of political violence was sealed off institutionally. The fact that the blade used to assassinate Okubo is preserved at the Metropolitan Police stands as a living witness to the historical turning point when the katana transitioned from "the age of the weapon" to "the age of cultural heritage," continuing today to convey its profound significance. From the Kioizaka Incident to the establishment of the Japan Sword and Martial Arts Museum (NBTHK) in Showa 23 (1948), nearly 70 years passed; countless shin-shintō blades born in the same era as the sword used in the incident were preserved as artworks, surviving the storms of warfare and modernization. In this sense, the Kioizaka Incident stands as the event most symbolically demonstrating the historical watershed when the katana transformed from "weapon" to "cultural heritage," remaining eternally memorable in sword history.