A shuriken literally: “hidden hand blade”) is a Japanese concealed weapon that was used as a hidden dagger or metsubushi to distract or misdirect.
Shuriken came in a variety of forms; some were manufactured, while others were improvised from tools. The edges of shuriken were often sharpened, so they could be used to penetrate skin or open arteries.
Shuriken are commonly known in the West as throwing stars or ninja stars although they were originally designed in many different shapes. The major varieties of shuriken are the bō shuriken (棒手裏剣, stick shuriken) and the hira shuriken (平手裏剣, flat shuriken) or shaken (車剣, also read as kurumaken, wheel shuriken).
Shuriken were supplementary weapons to the sword or various other weapons in a samurai’s arsenal, although they often had an important tactical effect in battle. The art of wielding the shuriken is known as shurikenjutsu and was taught as a minor part of the martial arts curriculum of many famous schools, such as Yagyū Shinkage-ryū, Tenshin Shōden Katori Shintō-ryū, Ittō-ryū, Kukishin-ryū, and Togakure-ryū.