The kunai knife is a longtime favourite weapon for aspiring ninjas and a useful gardening tool for the modern Japanese household. Akin to a trowel, it has been used in East Asia for centuries for simple gardening and fieldwork. Due to its wide-scale production and availability, it was fashioned into a makeshift weapon by both vulnerable peasants and ninjas. The difference between the common kunai and the ninja kunai lies in the degree of sharpness. The ninja kunai is commonly known today for its role as a weapon of choice in the popular anime series Naruto. The ninja kunai has two uses, depending on its size.
Identify your kunai. Ninjas use several variations, and it is important to identify your kunai in order to implement its use successfully. Two types of kunai knives exist: large ones, used for thrusting and stabbing, and small ones, used for throwing. All other variations concern types of blade. If your knife's blade is 4 to 5 1/2 inches long or roughly the same size as your extended hand, it is a throwing kunai. If the blade is longer, it is a thrusting kunai.
Thrust your kunai. A thrusting kunai is used very much like a dagger. Because the kunai does not have a guard, the most effective way to hold it is to wrap your hand around its hilt by making a fist. Find a stable stance, and commence to make short sharp jabs at the object you wish to stab, such as a medium-sized cardboard box.
Throw your kunai. A throwing kunai is used much like a throwing star. Get into a stable stance in order to project your kunai accurately. This can be done by leaning one foot forward and slightly bending your leg. After this, make an L shape with your finger and thumb while holding your arm back. Hold the dagger facing down by the handle. With a quick gesture, move your arm down. Do not move your wrist because it is your arm's force that will project the dagger.
Ensure you have a cleared space when using a throwing kunai.
Do not use on people or animals.