The Black Ninja Belt is a body item in Club Penguin Rewritten. It is currently unobtainable, but in the future it will be obtained as the highest (9th) tier belt on Card Jitsu. Getting this item will allow you to beat Sensei and obtain the Ninja Mask. In addition, earning this belt will result into a postcard from Sensei congratulating you, as well as the True Ninja Stamp.