A shuriken is a Japanese concealed weapon used by samurai or ninja or in martial arts as a hidden dagger or metsubushi to distract or misdirect.
Five types of shuriken
Edo period shuriken in Odawara Castle Museum, Japan
Four antique forged Japanese bo shuriken (iron throwing darts with linen flights)
Various types of shuriken at the Iga-ryū Ninja Museum
A ninja or shinobi was a covert agent, mercenary, or guerrilla warfare expert in feudal Japan. The functions of a ninja included siege and infiltration, ambush, reconnaissance, espionage, deception, and later bodyguarding and their fighting skills in martial arts, including ninjutsu. Their covert methods of waging irregular warfare were deemed dishonorable and beneath the honor of the samurai. Though shinobi proper, as specially trained warriors, spies, and mercenaries, appeared in the 15th century during the Sengoku period, antecedents may have existed as early as the 12th century.
Drawing of the archetypical ninja from a series of sketches by Hokusai. Woodblock print on paper. Vol. six, 1817.
In Sakura doki onna gyoretsu, this onnagata is attended by three kuroko.
Yamato Takeru dressed as a maidservant, preparing to kill the Kumaso leaders. Woodblock print on paper. Yoshitoshi, 1886.
The plains of Iga, nested in secluded mountains, gave rise to villages specialized in the training of ninja.