The Japanese bo shuriken, or throwing spike, is a relatively little-known throwing knife with a long and somewhat mysterious history. Modern knife throwers incorporate it into their arsenal and use a technique very similar to the one they use for standard throwing knives. The throwing spike is fairly heavy, and the thrower must hit his target with it very squarely for the spike to stick. As with all martial throwing arts, spike throwing is dangerous, and practitioners should be certain that no one will walk through their line of fire when they are practicing.
Stand facing your target with your right foot about two foot-lengths behind your left and your weight on the ball of your right foot. Align your heels, and turn your right foot out 45 degrees. Bend your front knee and keep your back knee loose and flexible.
Hold the spike in your right hand the way you would hold a hammer, with the body of the spike against your palm and your thumb along its side. Because of the location of the spike’s center of gravity, you can hold either end of the spike and throw it successfully. Hold it from the handle or the tip according to your own preference. Stiffen your wrist so it will not bend when you throw.
Straighten both your arms in front of you and point them toward the target. Keeping your left arm aiming forward, swing your right arm upward and back so the spike is level with your head. Swing your arm forward and shift your weight to your front foot. Just before your throwing hand reaches the level of your aiming hand, release the spike toward the target, keeping your wrist stiff.
As the spike flies, follow through on your swing with your body. Allow yourself to travel forward with your own momentum. This fluidity in your body helps the spike stick in the target.
Practice until you are consistently sticking your spike. Be patient. Finding the right balance of force and relaxation may take some time. When you have developed the muscle memory of where to release the spike, practice throwing without using your left arm to aim.