The bagh nakh or »tiger claw« is an Indian concealed weapon, a sort of augmented knuckleduster. Rings on the index and little fingers (or sometimes on all fingers, as on typical knuckledusters) attach to a plate or bar along the inside of the knuckles of the palm. Attached to this bar are four or more curved blades, sharpened on the inside of the curve, so that they follow the curvature of the fingers when the hand is relaxed. The best form of bagh nakh, although rare (I myself have only seen two historical such pieces), have flat plates jointed together at the edges down the entire palm, attaching to a second bar connected to a thumb-ring, thus letting the wearer grab an edged weapon with some chance of remaining unharmed. The weapon is used by raking slashes and slaps (which become stabs) with the open hand, causing superficial, painful but typically non-lethal injuries — although no doubt a slash along the throat would be hard to just shake off.
Bagh nakh are variously claimed to be a weapon of assassination, a woman's self-defense weapon, or a parrying sidearm developed by the Sikh Nihangs, and it certainly seems in many ways to be designed for protection. However, the only really well established historical use for them was as part of a particular form of wrestling called »claw grappling«, a bloody spectacle in which bhang-addled wrestlers slashed each other to gory piles of human tagliatelle for the amusement of their rulers; possibly not an ideally respectable application.
Bagh nakh also exist on which the knuckle bar extends into a knife blade on one or both ends; in this case, it resembles a hybrid between the more typical tiger claw and a kerambit.