I'll try to find some stuff about the Shinsengumi
. This might be hard to find though.
ADDITION:
I found information on the Ikeda-Ya incident though.
Ikeda Inn Incident was a famous armed encounter between the anti-shogunate forces from Chosu (now Yamaguchi) and the Shinsengumi on July 1864 in Kyoto, Japan. The anti-shogunate forces were planning to set fire in Kyoto and overthrow the Aizu clan who were policing Kyoto at the time. The Shinsengumi figured out their plan and slaughtered them before they could carry it out. There was only one death on the side of of the Shinsengumi. This incident made it clear in Kyoto that the Shinsengumi were a strong force to be feared by the anti-shogunate.