Katana isn't rare. The reason you don't see a lot of people wearing it, is due to the fact that it is the dumbest armor piece you can wear. It makes you a bigger target, and I've been sniped multiple times from people shooting my katana. For a competitive Halo 3 player, wearing the Katana makes you look and feel stupid. All in all, the Katana isn't rare, it just sits in everybodies inventory waiting for the next retard who decides to put it on.