If you've spent any time talking to Quentin Tarantino or listening to the pear-shaped vitriol seeping out of comic conventions, you know that the Japanese katana is essentially magic. Not since Nintendo or hentai has some quirky Japanese perversion of a mundane invention had so much cache among doughy white people with unsettling OKCupid profiles. Katanas are sharp and strong enough to cut cleanly through bone, metal, armor, and probably even the sun, if only someone could get close enough. That's all because of one very important reason: The steel has been folded over thousands of times, creating a weapon infinitely superior to shitty ol' non-folded metal. Somehow this strange Asian tradition remained a mystery to those idiot Europeans for thousands of years, which is why Bruce Willis didn't head for the broadsword aisle when he had some serious rape-stopping to do in Pulp Fiction.
"Only a Japanese blade can end something this perverted."
But actually ...
First of all, you don't need to fold good steel. Japanese swordsmiths used a metal known as tamahagane. It sounds fancy as hell, but so does anything you say in Japanese. Westerners knew tamahagane as "pig iron," which is considerably less romantic. They refused to use it in the west for weapons, not because they were stubborn morons but because it's loaded down with carbon and too much carbon will turn your sword into a brittle shower of metal shards during its first use. See, the process of folding a sword started as a way to iron out that extra carbon in a shitty alloy, turning pig metal into something more suitable for stylized murder.