On March 25, 1869, in the Naval Battle of Miyako Bay, Kōtetsu successfully repulsed a surprise night attempt at boarding by the rebel Kaiten (spearheaded by survivors from the Shinsengumi), essentially thanks to the presence of a Gatling gun on board.
In the SNK game The Last Blade the character Washisuka Keichiro, a member of the Shinsengumi, is sent to this place to "investigate" in his ending.
Nobuhiro Watsuki has stated that the character design of Sōjirō is loosely based on Okita Sōji, the captain of the first Squad of the Shinsengumi.
Even without Itou's support, Takeda ambitiously planned to leave the Shinsengumi, contact Satsuma and start a new movement to overthrow the shogun.