After Japan opened up to the West in the 1860s due to U.S. Commodore Matthew Perry's visits, sentiment towards the Tokugawa shogunate grew negative while citizens longed for the return to power of the emperor. In response, the Aizu clan, with the shogunate, hired some of the greatest swordsmen of Edo and masterless samurai in Kyoto to protect itself and counteract those who supported the emperor against the Tokugawa shogunate. They were originally composed mainly of samurai from Chōshū (now Yamaguchi Prefecture). The Shinsengumi's greatest enemies were the imperialists-supporting ronin samurai of the Mori clan of Choshu (and later, former ally Shimazu Clan of Satsuma.)
The Shinsengumi began as the Rōshigumi. Later, thirteen members of the Defenders became the thirteen founding members of the Shinsengumi. The Shinsengumi was also called the Miburō, meaning "Wolves of Mibu", after the town where they were stationed. Originally, it meant the "ronin of Mibu", but this changed as the reputation of the Shinsengumi became tarnished in its early years. Shinsengumi could be translated to "Newly Selected Corps" (Shinsen means "new chosen (ones)," while "gumi" translates to "group," "team," or "squad.")
The original Commanders of the Shinsengumi were Kamo Serizawa, Isami Kondō, and Nishiki Niimi. The group was made of two factions with Serizawa's Mito group and Kondō Isami's Shiekan dojo members. They based themselves in the Mibu neighborhood of Kyoto. The group submitted a letter to the Aizu clan requesting permission to police Kyoto to stop the actions of revolutionaries and lawless samurai. Their request was granted, but ironically, the reckless actions of Serizawa and Niimi, done in the name of the Shinsengumi, caused the group to be feared in Kyoto when their job was to keep the peace. Their reputation improved after Niimi's forced seppuku and Serizawa's assassination, facilitated by the faction under Kondō's command.
The Ikedaya Affair of 1864, in which they prevented the burning of Kyoto, made the Shinsengumi famous overnight and they had a surge of recruits.
The Shinsengumi remained loyal to the Tokugawa bakufu, and as the latter collapsed, they were driven out of Kyoto. They fought to the very end. Isami Kondō was captured and beheaded by the Meiji government. Generally, the death of Toshizō Hijikata on June 20 (lunar calendar May 11), 1869 marks the end of the Shinsengumi.
There were a few core members, such as Shinpachi Nagakura and Hajime Saitō who survived the demise of the group.
Members of the group
At its peak, the Shinsengumi had about 300 members. They were the first samurai group ever to allow those from non-samurai classes like farmers and merchants to join because Japan had always had a strict class hierarchy system. Many joined the group for the desire to become samurai and be involved in political affairs. However, it is a misconception that most of the Shinsengumi members were from non-samurai classes. Out of 106 Shinsengumi members (among a total of 302 members at the time), there were eighty seven samurai, eight farmers, three merchants, three medical doctors, three priests, and two craftsmen. Quite a few leaders such as Yamanami, Okita, Nagakura, and Harada were born samurai.