This YouTube channel has a lot of good info about different historical swords https://www.youtube.com/@scholagladiatoria https://www.youtube.com/@scholagladiato

This YouTube channel has a lot of good info about different historical swords https://www.youtube.com/@scholagladiatoria https://www.youtube.com/@scholagladiatoria - pretty sure he covers the difference in metallurgy between Japanese & European swords The main thing I've heard is that in Europe all the best swords used spring steel, which is hard enough to cut really well while also being able to flex without getting chipped, broken or bent. Japanese smiths couldn't make spring steel for various reasons, so as a workaround they used differential hardening, etc. to make the cutting edge super hard, while the back & sides ended up more ductile. It works pretty well, but the cutting face is still a little bit brittle & the sword as a whole ends up heavier & vulnerable to getting bent b/c it doesn't snap back into shape like spring steel would