That brown weapon is a "kama" (鎌) which means "sickle" - although IIRC (and this is digging back into my childhood memory here, so I don't know how accurate it is), Playmates referred to it as a "Kusarigama" (鎖鎌) which means "chain and sickle", even though there's clearly no chain attached to that accessory. Or maybe I just used to call it a "Kusarigama" when I was a kid and Playmates didn't call it anything... I dunno.

It is a traditional ninja weapon as the sickle is obviously a farming implement and ninja were peasantry (unlike Samurai who were of warrior nobility). I mean, they were visible peasants in their civilian guises... once they went into ninja mode, nobody could see them! (unless they were incompetent ninja ) We just guess that a ninja's outfit was black, but it could've been white, day glo yellow or hot pink... doesn't matter what colour a ninja's outfit is since you'll never see him! (muahahaha!)