Ryū ga Gotoku Ishin!

Ryū ga Gotoku Ishin! is a spin-off game in the Yakuza series.
Set in the chaotic Bakumatsu period (during and shortly after the American Civil War), Sakamoto Ryoma, is distressed resulting from conflicting pressures and uncertainty about one’s self and role in the society. Being embroiled in the middle of a Tosa coup d’état and bent on finding the murderer who assassinated his mentor, Ryoma burrows himself with a hidden identity in the streets of Kyoto and joins the grim Shinsengumi.