Generally, any knife can be used as a throwing weapon, but the accuracy of the hit greatly depends on the equilibration, the balance between the length and weight of different knife parts. In addition, in field conditions, a throwing knife should be well balanced, have no guard so as to improve balance and aerodynamic features, have the potential to inflict damage, and be fairly cheap because they can be easily lost.
A classic throwing knife is a plain metal platen divided into a blade and a handle, which have nearly the same width, and are separated only by a small stopper or a hollow. The blade is leave-shaped and is usually sharpened at its front edge. A handle often has an aperture or a ring through which to pull a thread. Sometimes throwing knives are dagger-pointed, which also allows one to use them effectively in close combat. Some special forces units use throwing knives, which have a form and sharpened edge similar to ordinary combat knives but can also be thrown at a distance of only 3 meters.
Shurikens or so called ninja stars are a type of throwing knives widely used in the East. Shurikens blades are formed from 3 or more blades that are evenly placed in a circular pattern so there is a high likelihood of hitting the target. Unlike other throwing knives, shurikens are to be thrown horizontally like throwing disks. Despite common belief, shurikens are not that damaging because their design does prevents from deep wounding. In the Middle Ages, shuriken blades were often covered with poison to increase their effectiveness as weapons. Some African tribes used to have knives similar to shurikens in their arsenal, but those knives were furnished with handles.