depends what sword it is... if it was the wooden ones that you see on training with those swords i think it isn't as bad as it acts liek a baseball bat.. however some people likes collecting samurai swords (the sharp ones) and for that i think it is overdoing it, burglary doesn't deserve the punishment to die...
to be honest, if you kill them or physically hurt them before they hurt you then you could be done for "bodily harm" and then have them filing against you. But if they attack you, self defence is allowed, but I dont think murder is. Of course in the situation, no one is going to think that, and I for one believe in "Eye for an eye, tooth for a tooth"...in a more extreme way... you rob my house, I rob you of your capability to walk... something along those lines. Tough luck he picked the guy with the samurai sword.
