Just to annoyingly go back to the topic of swords, my friend Nigel has trained with one and because he is big and strong he can use a heavier sword than most people and apparently he can gain an advantage by whacking an oponent's sword in a way that threatens to damage it. This puts his opponents at a disadvantage because they have to struggle to protect not only themselves but also their weapon. I realize this is not the same as cutting a sword with a sword, but I imagine this tactic could have resulted in a lot of broken swords in actual historical use.