Through the Blades of Grass in the Field of Kusa Fly...Shuriken

Shuriken, a weapon of the ninja that people know so well. Or so they think.

Shuriken are portrayed as great throwing weapons utilized by the shinobi in many media aspects of Japanese culture. They originated from tools just like many other weapons any any culture, but just as any weapon they had their purpose.

My main question; What were some of the origins of all the different variations of the Shuriken floating around throughout history?

Do you think you can fill in some of the blanks in The Field of Kusa???