Soshite Nakama ga Mata Hitori (S01E05)

Kenshin confronts Sanosuke, who wields the giant Zanbato with ease. However, Sanosuke shows his incredible durability after withstanding a strike from Kenshin with ease. This leads Kenshin to instead launch a barrage of blows at him, and Sanosuke falls to the ground. For a moment it looked as if victory has been decided. However, while Sanosuke is in a daze, he recalls the reason for his obsession with victory, his past from ten years ago when he was in the Sekiho Army... (Crunchyroll)