A uniquely designed kunai made from a special metal that can be only be found in the Land of Earth. Due to the unique properties of the metal, the kunai can be infused with any elemental chakra including Yin and Yang. In addition the kunai can also absorb chakra from any source, including the user as well as the opponent and as a result, the more chakra it absorbs the tougher it becomes. There is a limit to how much chakra can be stored within the chakra kunai, although the exact limitations are unknown as of now. It can be used to produce a variety of effects, depending on the user and the elemental chakra nature absorbed.