A throwing knife is used in the sport or art of throwing knives. Throwing knives are used in specific martial arts disciplines as well as for some circus shows and sport exhibitions. Throwing knives are used by many cultures around the world, and as such different tactics for throwing them have been developed, as have different shapes and forms of throwing knife. Throwing knives are commonly made of a single piece of steel or other material, without handles, unlike other types of knives. Throwing knives are made in many elaborate designs. Since most typical throwing knives have a long double edged blade, a slot sharpener is the best tool to use. 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. In the popular young adult novel and movie "the hunger games", clove uses throwing knives as her weapon of choice.