@Kairouseki:
You'd think the strongest swordsman in the world using the strongest sword in the world would be able to cut anything. And as juju says all he basically did was flip his wrist .
From what he said B4 I'm pretty sure he did put a lot into that attack. And I don't think it would B completely fair if he could cut anything. Mihawk is the world's best swordsman and if he is ever going 2B beaten in a sword fight by Zoro, Zoro will need room 2beat him and do something no other swordsman could. And it was kinda hinted by Mr.1 that Zoro would end up cutting diamond in the future.
=D