I'm a sword guy. I spent over a decade training in historical swordsmanship (mostly European longsword - a mix of Fiore and Lichtenaur; but also a little kenjutsu).

There are so many bad takes about swords out there, but I think my personal "favorites" are about the folded steel technique used to forge katana.

See, to make a good sword, you need good steel which is iron + carbon. More carbon = harder steel. Harder steel is better for holding an edge, but also less flexible and more likely to shatter. All swords, European, Japanese or otherwise had to balance those concerns.

Anyway, in Japan, their katana forging technique used steel with slightly differing carbon amounts wrapped in layers in the blade. This layering had a couple of important metallurgical effects:

1. It gave the core steel a more consistent quality. Since the method they had of producing steel contained varying levels of carbon, the repeated layering, folding, heating and hammering evened it out.

2. The layering also increased the strength of the steel. By adding layers of high and low carbon steel, the sword smiths could control the flexibility vs strength of the core.

Ok, so without getting too deep in the weeds, that's (basically speaking) why katana were made of folded steel.

But I have been "informed" by so many people that folded steel:

• Creates an edge like a thousand razor blades!
• Makes katana stronger than modern steel!
• Makes katana stronger than European swords! (steel-wise, it's a wash, though later blade geometry techniques like fullers arguably give European swords the - ha - edge in durability.)

In summary: katana are great - but not magic! The folded steel technique enabled forging swords of high-quality, consistent steel at a time when that was really hard to do. But that's it.

/self looks at rant

Uh... Thank you for coming to my TED Talk.