Bunkyū Era — Swords Between the Sakuradamon Incident and the Shinsengumi

The Bunkyū era (1861–1864) represents one of the most rapidly accelerating phases of late-Tokugawa political crisis. The Sakuradamon Incident of the third month of 1860 — the assassination of Great Elder Ii Naosuke by Mito rōnin just outside Edo Castle — delivered a powerful message to sonnō-jōi activists across Japan: swords could still determine the course of history. The unprecedented spectacle of a senior shogunal official cut down in broad daylight before the castle gates exposed the shogunate's vulnerability and spread a radical conviction among activists that a blade in the hands of a determined man could change the political order.

The dominant feature of Bunkyū-era sword culture was the surge in demand for swords with political purpose. As the sonnō-jōi movement intensified, activists from Mito, Satsuma, Chōshū, and Tosa domains became actively engaged in acquiring practical combat blades. The Namamugi Incident of Bunkyū 2 (1862) — Satsuma retainers killing a British merchant — and Chōshū's bombardment of foreign ships in Bunkyū 3 (1863) were among the incidents in which sonnō-jōi conviction translated into violent action. These events embedded the sword in the political imagination as both an implement of assassination and a symbol of national will. The selection and acquisition of swords became a significant practical concern for activists.

The sword industry faced significant pressure to respond to this unusual demand. In Edo's sword markets, high-quality shinshintō blades became objects of activist aspiration — works by Minamoto Kiyomaro (who had died in 1854 but whose blades continued to circulate), Koyama Munetsugu, and Kurihara Nobuhide were particularly prized. Simultaneously, demand for affordable practical blades surged, and smiths across Japan took orders without regard to their customers' political affiliations. Major activist domains such as Chōshū and Satsuma developed organized systems for procuring and managing domain sword arsenals.

Emperor Kōmei's jōi (expulsion) imperial order of Bunkyū 3 (1863) and the shogunate's simultaneous installation of political supervisors in Kyoto shifted the focus of Bakumatsu politics to the imperial capital. In the eighth month of 1863, the Coup of August 18 expelled Chōshū forces from Kyoto, but the city remained a zone of armed confrontation in which rōnin, loyalist activists, and shogunal forces mingled with swords drawn. The organization and activation of the Shinsengumi (initially the Mibu Rōshigumi) from Bunkyū 3 (1863) through Genji 1 (1864) was the shogunate's organized response to this armed street-level conflict.

The Bunkyū era is a transitional period in which the sword's positioning shifted once more — from "the samurai's cultivated possession" back to "instrument of political assassination and direct action." The collision between shinshintō idealism (the restoration of classical beauty and technique) and Bakumatsu reality (the sword as the frontline tool of political violence) gave Bunkyū-era sword culture its distinctive charged quality, embodying the coiled tension of the moment immediately before the Keiō explosion.