Those of you who have seen Shogun assassin or any of the Babycart series of films will be familiar with Ogami Itto, the rogue samurai turned sword for hire and one-man slaughterhouse. His adventures were first described in the comic book series "Lone Wolf and Cub", written in the seventies and covering 28(!) volumes in which the man himself and his toddler son kill most of Japan with his trusty Dotanuki sword. The Dotanuki was a battlefield sword with a heavier blade than most carried at the time that could "cut through armour like paper" and could cut through enemies, break swords and even cut a ship's mast in twain without losing its edge.
The story of Lone Wolf and Cub would have been a bit shorter if Itto had bought his sword from the Home Shopping Network.