These knives in the picture to the left are typical examples of professional throwing knives. Learning to throw knives with any kind of accuracy takes practice and dedication. The thrower has to learn how to hold the knife to best throw it, how to judge the distance between him and his target, how to figure out the velocity-to-spin ratio so he knows how hard to throw the knife, and several other factors. It's not easy.
	These are one type of shuriken, also called throwing stars. These are much easier to use, because the multi-point configuration ensures that the star will stick. The best way to throw them - that I have found, at least - is with a quick backhand wrist snap, like you were throwing a frisbee. I said they were easier to throw than knives, but if you were a ninja in feudal Japan, extensive training was necessary to ensure that the shuriken hit the target in a lethal area (such as the neck) if the ninja wanted the stars to be lethal weapons instead of mere nuisance objects.
	These are the other type of shuriken, called spike shuriken. It had been thought that to throw these you had to use the same methods for throwing knives, but a man named Shirakami Ikku-Ken has devised a way to throw spike shuriken that produces a rotationless throw. He talks about it in his book, Shuriken-Do.
	This is a throwing axe. These are much easier to throw since the heavy head basically ensures that it will hit the target and stick like it should. There's still some technique to doing it right, but the novice thrower would do better with an axe than a knife.