well said. This is correct. European swords, not all, have tendency to bend after repeated contact. It wasn't uncommon to see fighters bending their swords back into the proper shape mid-battle. This would never happen with a Katana.
I don't know if you get coloring on Katanas but I really like the look that old fire baked case hardening gives.
Couldn't find a good pic of a sword.
That's maybe a little too rainbowey for my taste but you know what I mean. I'm sure I've seen Cavalry swords with a similar effect.
