OK, 'legitimate' is a loaded term. Let us simply say that 'kendo' is listed as a martial art, whereas 'throwing a great big shield so that it bounces off walls' is not. And no, I'm not saying that they never use anything else, just that they predominately use the martial arts. A gun and a cyborg arm are added bonuses - when Misty runs out of bullets, she kicks ass kung-fu style. Yes, you would be allowed to use shuriken - shuriken are weapons used by ninjas, who are martial artists. Therefore, they count as a martial arts weapon. It's perhaps cheating a little, but no more than ninjas do. And they differ substantially from Batarangs in that Batarangs are just boomerangs with batwingy edges, and a boomerang is not a martial arts weapon. It's an Aboriginal hunting weapon - you throw it, it hits the kangaroo, or it misses, comes back to you, you throw it again, THEN it hits the kangaroo. It's purely utilitarian - you couldn't fight a duel with it. (Well, you could TRY, but I think both parties would spend more time waiting for the bloody thing to circle around and come back than they would throwing it.) Batman happens to have a very accurate aim, and so most of the time his 'rangs hit the bad guy in the head, thereby skipping the 'circling around part'. Furthermore, a boomerang is largely non-lethal - it can certainly be a deadly weapon in the right hands, but it can just as easily knock someone out. Shuriken, on the other hand, are intended to slice you up into little bitty pieces - when they're used correctly, they are almost ALWAYS lethal. And no, of course I'm not saying that using intimidation doesn't make you a proper martial artist. I'm simply saying that intimidation, in and of itself, has nothing to do with martial arts - no one teaches you 'looming menacingly and using a scary voice' in karate class.