In 14th century Japan, there were two famous gunsmiths - Masamune and Muramasa. Once they had a duel with each other: they stabbed the sword they made into the bottom of a small stream, blades against the current. And the leaves floating in the stream were cut in two by Muramasa's sword, while Masamune's sword was bent around without touching. Those swords were called katanas.
Do you know how that fight ended? Muramasa admitted to being defeated. After all, the philosophy of samurai kenjutsu says: the sword should not carry cruelty and danger, but peace. And its main purpose is to prevent the outbreak of war by any means. The case with the katana, which went down in the history of this weapon, is classic for kenjutsu.