Throwing knives are commonly made of a single piece of steel or other material, without handles like other types of knives. The knife has two sections, the 'blade' which is the sharpened half of the knife and the 'grip' which is not sharpened. The purpose of the grip is to allow the knife to be safely handled by the user and also to balance the weight of the blade.
The knives are of two kinds, balanced knives and unbalanced knives. A balanced knife is made in such a way that the center of gravity is at the center of the knife. Such a balanced knife will follow a near circular trajectory in the flight. For an unbalanced knife, the center of gravity does not match the geometric center. If the knife's handle is heavier, then the circles of the handle and the circles of the blade in flight will be of different diameter, making the trajectory less predictable. The unbalanced knives are generally thrown by gripping the lighter end. There are also knives with adjustable weights which can slide on the length of the blade. This way, it can function both as a balanced or unbalanced knife depending upon the position of the weight. Balanced knives are generally preferred over unbalanced ones for two reasons: Balanced knives can be thrown from the handle as well as from the blade and it is easier to change from one balanced knife to another.
The weight of the throwing knife and the throwing speed determine the power of the impact. Lighter knives can be thrown with relative ease but they may fail to penetrate the target properly resulting in "bounce back". Heavy throwing knives are more stable in their flight and cause more damage to the target, but more strength is needed to throw them accurately.