Sorry, but I can't tell you. I'm pretty sure that defeats the entire purpose of the club.

[Even though there were definitely applications available to everyone in the entire school via pamphlet announcing the existence of a Ninja Club... It's probably best for him to just leave it at that.]

You could probably call it a sports club, though. And before you ask, it's not any kind of fighting, either. [Not that any school would let its students get away with carrying around knives...]