Shinsengumi Formation Day

What Is Shinsengumi Formation Day?

Every March 13th is another "Shinsengumi Day" in Japan. On March 13, 1863, the "Mibu Rōshi-gumi" (壬生浪士組, Mibu Masterless Samurai Corps) — the immediate predecessor of the Shinsengumi — came under the official protection of the Aizu domain lord Matsudaira Katamori (松平容保), who had been appointed Kyoto Military Governor (京都守護職). This patronage relationship formally established the corps as an arm of official Kyoto security, giving the group that would become the Shinsengumi its institutional foundation. (See also February 27th for the Shinsengumi's earlier background.)

The Aizu Connection

The Aizu domain's patronage of the Mibu Rōshi-gumi was not coincidental — Matsudaira Katamori and the Aizu domain were among the most loyal Tokugawa supporters, and the appointment of Aizu as Kyoto Military Governor reflected the Shogunate's desperate need to maintain order in a city roiling with anti-Shogunate activists. The samurai corps that became the Shinsengumi served directly under Aizu patronage, explaining why Shinsengumi members maintained their loyalty to the Tokugawa cause through the Meiji Restoration and beyond — to the ultimately fatal Battle of Hakodate in 1869.

The Shinsengumi's Kyoto Operations

Based at the Mibu neighborhood of Kyoto, the Shinsengumi developed into an effective — if feared — security organization. Their strict internal code (局中法度, kyokuchū hatto) enforced discipline through seppuku for violations; their swordsmanship was exceptional; and their intelligence network made them effective at identifying and neutralizing anti-Shogunate conspirators. The Ikedaya Incident of July 1864 — in which they raided a meeting of revolutionary samurai, killing or capturing many — was their most famous action and briefly shifted the political balance in Kyoto.

Fun Facts

• Blue uniform: The Shinsengumi's distinctive light blue (浅葱色, asagi iro) haori (short jacket) with white "mountain" (山形, yamakei) pattern has become their most recognized visual identifier, appearing in virtually every dramatization of their story and making the "Shinsengumi blue" instantly recognizable in Japanese popular culture.
• Kondō's fate: Shinsengumi commander Kondō Isami was captured by imperial forces after the Boshin War and executed by decapitation in April 1868 — the same month the new Meiji government was effectively established. His grave is maintained at Itabashi in Tokyo, where dedicated fans regularly leave offerings.