User blog comment:Fairy Tail Grand Master/What is the hidden blade made of?/@comment-4636255-20120627163359

Pressure=Thrust/Area. :P

Hidden Blade has tiny area at the top. Plus, he never actually used it for parrying other attacks that much, so it wouldn't get blunt fast either. And if a sword can go through when we stab from the bag, why not the hidden blade as well?