I was obsessed with the "throwing star" as a kid. That all ended when Dad found the strange holes in the fence... I blamed squirrels of course - the end of my experience... This is just a cut and paste from Wikipedia:
"Contrary to popular belief, shuriken were not primarily intended as a killing weapon, but rather as a secondary weapon that sometimes played a role supportive to a main weapon, usually the sword or spear. Shuriken were primarily used to cause either nuisance or distraction. Targets were primarily the eyes, face, hands, or feet—the areas most exposed under armor. The shuriken would sometimes be thrown in a way that cuts the opponent and becomes lost, later causing the opponent to believe that they were cut by an invisible swordsman.
Shuriken, especially hira-shuriken, were also used in other novel ways—they might be embedded in the ground, injuring those who stepped on them (similar to a caltrop or makibishi), wrapped in fuse to be lit and thrown to cause fire, or wrapped in a cloth soaked in poison and lit to cover an area with a cloud of poisonous smoke. They can also be used as a handheld striking weapon in close combat.
There are reports of shuriken being coated with poison, intended either for a throwing target or for whoever may pick them up when left in a conspicuous place. Other reports indicate that shuriken may have been buried in dirt or animal feces and allowed to harbor the bacterium Clostridium tetani—if the point penetrated a victim deeply enough, the bacteria transferred into the wound could cause a then-incurable tetanus infection."
I am sure some of you here remember this "shuriken"
shu = "hand" (it's another way to say the same kanji for "te", as in kara-te "empty-hand," or shu-to "blade/knife-hand," better known as a "karate-chop"
ri = "hidden," or "concealed," and...
ken = "blade"