from web site
Throwable Japanese hidden weapon A (Japanese:; literally: "surprise hand blade") is a Japanese concealed weapon that was used as a surprise dagger or metsubushi to sidetrack or misdirect. Additional Info are likewise understood as tossing stars, or ninja stars, although they were initially developed in various shapes. The significant varieties of shuriken are the b shuriken (, stick shuriken) and the hira shuriken (, flat shuriken) or shaken (, wheel shuriken, also read as kurumaken).