I thought Ishin was the only one set in feudal Japan.
Yup they two Samurai games.
Kenzan was released in 2008 and was the game in the series for the PS3, had you playing as real life historical Miyamoto Musashi that had the personality and appearance of Kiyru.
Ishin released in 2014 as a launch title for the PS4 in Japan where they place as another real life historical figure Sakamoto Ryoma, that also had the personality and appearance of Kiryu.
I am fully expecting the first Yakuza game for the PS5 to be another Samurai spin off.