SHURIKEN

Shuriken are a close-to-midrange weapon that was used by the ninja.  This unique weapon is one of the most commonly known weapons of the ninja and the mere mention of them draws the stealth warriors to the minds of many people.  Ninja could use them to attack pursuing enemies without stopping.  A quick turn and a flick of the wrist usually resulted in the sharp blades of a shuriken embedded in the enemy.  Due to the many sharp sides of a shuriken, it was able to be thrown and almost always find at least some target.  It was difficult to throw them effectively, but a trained ninja could throw them with perfect accuracy, dispatching enemies and continuing on with their mission.  There were various shapes and sizes to shuriken, so at any given time, the blacksmith in a ninja village was busily at work.

Shuriken also included kunai and rocks and just about anything that could be thrown at an opponent.  Kama (scythes) could even be thrown at an enemy, with grisly results.

Hold the shuriken similar to how one would hold a dart

Despite what is shown in movies, it is a bad idea to try to throw shuriken as if dealing cards

A stack of shuriken lies in the palm of the hand

The palm of the other hand rests atop the pile

Sling the shuriken out as if dealing cards

In addition to the star-shaped shuriken commonly seen in movies and comics, there were also stick-shaped shuriken known as bo shuriken.  They usually had one end sharpened into a point and was used for striking vital areas (eyes, throat, wrists, etc) in order to disable or kill an opponent.

Bo shuriken can also be either thrown or used as a stabbing weapon.  I realize that this is a pen, but the same principles apply.