In 1868, Tatsunosuke left the Koyochinbutai (the renamed Shinsengumi) after the Battle of Kōshū. However, Tetsunosuke decided to stay with the group. He continued to fight in numerous battles.
During the final battle of the Boshin War, the Battle of Hakodate, Hijikata summoned Ichimura on April 15 (lunar calendar) or May 3 (lunar calendar) 1869, to a private room in an inn.
There, Ichimura was entrusted with a death poem, Hijikata"s katana, a letter, a photograph of Hijikata, and several strands of Hijikata"s hair. He was instructed to bear them to the home of Satō Hikogorō (Hijikata"s brother-in-law) in Hino.
Ichimura reluctantly carried out his orders, having truly wished to stay with his master and fight to the death. Ichimura learned of his master"s death on the boat to Yokohama.
Tetsunosuke arrived in Hino three months later.
When he arrived at Sato"s home he reported the news, and later recounted that there were none that did not weep. Tetsunosuke stayed at Sato"s house for two to three years. Later, he returned to Ōgaki and was reunited with Tatsunosuke.
There are a few theories regarding the date of Ichimura Tetsunosuke"s death.
While many believe that he joined Saigō Takamori"s army and died during the Satsuma Rebellion in 1877, some believe that he died from an illness in 1873. Therefore, the date of his death is uncertain.
Ichimura Tetsunosuke is the protagonist of the manga and anime series Peacemaker Kurogane, which focuses around the exploits of the famous Shinsengumi. He is 15 years old and rather short.
Ichimura is also featured in the anime series, Bakumatsu Kikansetsu Irohanihoheto, the short OVA Hijikata Toshizou - Shiro no Kiseki and Nippon Hōsō Kyōkai"s Shinsengumi!!: Hijikata Toshizo Saigo no Ichinichi.
Ichimura is also a supporting character in Shin Teito Monogatari, the prequel to the bestselling historical fantasy novel Teito Monogatari (Hiroshi Aramata).
Although commonly believed to be a fictional character, Ichimura Tetsunosuke was a real member of the Shinsengumi.