legs is trolling the entire community, no one would pay 20,000 for a katana and go and actually use it. BTW guys, not a single sword in the world could slash through a well made full plate armor. That is why in the late 15th and 16th century shields becames more and more obsolete, 2handed weapons became more common for the plated knight. Because of the arms and armor race constantly going on, weapons developed to counter this ofcourse, so european swords became sturdier and more pointy to be beter at stabbing. You might think stabbing would penetrate the armor, but barely, it might have gone through the armor, but let me remind you that there would be a gambeson underneath the plate. Not only that, but your weapon would be stuck in your enemies armor, so that would give your opponent(who might be lightly wounded or not at all) the chance to stab you in the face. So, to be able to do some serious damage to a knight in plate armor you would have to find gaps in the armor to stab through, usually those were located in the armpits, near the genetals and if the breastplate consisted of multiple parts, inbetween those. To counter this lame ass tactic there small patches of mail were sewn to the gambeson on the places that were less protected by the plates, these things are called plate companion sets.
Sincerely,
Your history teacher Berethorn