Gintama Season 3 Episode 40: Shogun Assassination Arc Part Six: Sworn Enemy
Episode 40 of 51 of Gintama Season 3, aired January 12, 2016, 25 minutes. Available with English subtitles and dub where released.
Episode summary
As Gintoki and Takasugi continue their frenzied fight, the past they shared together with Katsura is revealed, as well as the fate of their teacher, Shouyou.