A Shadi-féle videó egyik kommentje (alanwalker6708):

"Iron sand is awful ore, absolute crap. What the Japanese did well was the craftsmanship involved in converting awful steel ore into a decent weapon by embedding the small amount of high carbon steel they could make into the cutting edge. And expertly pattern welding and folding the awful impurities out. Veritasium got that wrong too, they showed the cutting edge carbon steel being a wrap over the top of the mild steel, when actually it was hammered into the centre when the mild steel was red hot. Basically san mai but only on the cutting edge creating a flexible spine and a hard cutting edge, and again Shad is right... a modern made katana made from purely spring steel or railway clamps differentially hardened would be a better sword if the same level of craftsmanship was applied as those ancient sword makers. "