Individual weapons in a variety of points, shapes, and sizes to practice Shurikenjutsu (the art of throwing a shuriken).
The ninja star is an ancient weapon of choice used to inflict damage and injury from a distance. Accurately throwing these shurikens were a hallmark of the Japanese Ninja.
Some martial artists still train with these. And for many, it is a sport similar to knife throwing.
Being able to hit your target consistently takes practice. But once you get the hang of it, you'll be hitting your target every time. Star throwing can be made into a fun backyard competition. All it takes is your stars and something to throw them at, such as the target board.
A small file may be used to sharpen or resharpen your stars.