Cybernetics, Prosthesis and Implant Design Jizai Arms Supernumerary Robotic Limb System by Team JIZAI ARMS Jizai Arms is a supernumerary robotic limb system worn on the body. The system consists of a wearable base unit with six terminals and detachable robotic arms, each with five degrees of freedom. The arms can be attached and removed quickly, so wearers can exchange arms with one another. Exterior parts are produced by three-dimensional printing, which allows complex shapes and reduces weight. The arms are operated through a half scale model moved by hand, and the posture of the model is applied directly to the robotic arms.