• swordsmanluke@programming.dev
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    1 year ago

    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.

    • Rakonat@lemmy.world
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      1 year ago

      The funny part is when you remind the weebs how bad the iron commonly found in Japan was just not great quality and purity which they lacked the know how to correct, so the folding technique was developed to make their steel workable. If European techniques had been used on Japanese Steel, you’d have one very shoddy sword.

    • DokPsy@infosec.pub
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      1 year ago

      I was under the impression the folding technique of Japanese blades was due to the low carbon content and the process of folding included adding carbon to the iron as well as incorporating it throughout the metal.

      European iron ore already had larger amounts of carbon which meant the folding and adding carbon process wasn’t required to create a serviceable edge.

      • swordsmanluke@programming.dev
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        1 year ago

        It’s a little bit of both.

        Iirc, Japanese iron was usually in sand form, gathered, rather than mined. So the raw material was smaller and contained less natural carbon than mined ore.

        (Though nobody had near the advantage of Indian steel from the Damasc region - Damascus steel naturally had more carbon in their iron and it made for very high quality steel at the time.)

        Anyway, at that time Europe had similar techniques for making iron into steel and normalizing the carbon. They would use more resource-intensive techniques, like stacking rods of wrought iron in a furnace with charcoal, then working the carbon-infused rods to distribute the carbon evenly.

        That works great when you have access to millions of square miles of forest (for charcoal) and loads of iron ore.

        But it’s not really about whose steel was “the best”, it’s just that the “folding” technique was a metallurgical process and had no impact on the quality of the sword (except insofar as it was turning iron into steel).

        • DokPsy@infosec.pub
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          1 year ago

          Oh for sure on all points.

          I was just saying that the intensive folding process wasn’t nearly as necessary for the euro smiths. Especially, as you said, they had more than enough carbon sources to make up for any deficits in their iron sources.

          Once the smith turns the raw material into steel, there was very little difference beyond what the final product needed in hardness/flexibility.