Originally posted by: SideLabel
Welll Hokage-IV, that's a good question.

The way I see it, there is a difference between a knife, and fire. One is physical, being the knife, and fire is not. Now before anyone starts going all science on my ass (yes I know fire is also physical), let me exlain. A knife will always have the same mass, while a fire will roar up, sink, be blown in all directions, etc. It can also die out in a moment. The knife will always go in the direction you throw it and affected very little by wind. When there is wind combined with fire, you have a big-ass problem on your hands.

To answer your question, yes, Orochimaru could certinally be killed by a standard weapon. He may be one of the strongest ninjas alive, but he is still only human. I base this simply on the "physical" theory in the above paragraph. For one, if Orochimaru didn't bring up his defenses against a fire jutsu, he would most likely be burned alive. If he got a knife stab in the heart, he'd still die. The reason? Using a weapon is not a ninja technique, so to speak. There is no way to build up resistance to a weapon. Sure, you can deflect weapons with other techniques, but there is no way you have a jutsu defense for something that is not a jutsu.

That is also the reason I think ninjas use weapon. The options for countering them are few. You can either, catch them, dodge them, or be hit by them. The last being the least prefferrable.

This is very complex because there is so many aspects to it, and i think ur theory is pretty good

As for me , I don't think Kishimoto is following certain laws that can be indentified precisly . For Example, We know there is gravity in Naruto cuz they cant fly, but they can jump like 50 feet up high and somtimes they can jump 100 feet up high . So which law is he following? the gravity is the same but the ninjas are physically much stronger and their chakra, adds to the equation . which we know its anamoly how much if effects or , is gravity was just simply been modified which is not the same as the real world.

mass theory makes sense and it clears up quite a few things . but if there is a ninjutsu defense , do you consider running away from the jutsu a defense? or do they only have defense against fire? certainly element jutsu are comparable with each other in terms of lvls . we see that they can stand in fire and not get their skin burnt off. Also we ccan see they avoid water jutsu and if they get caught like zabuza did ,we can see the effect of it and that was against his own jutsu.

personally i dont think there is a defense, well actually i do, its called ego