A ninja (Japanese: 忍者, lit. 'one who is invisible'; [ɲiꜜɲdʑa]) or shinobi (Japanese: 忍び, lit. 'one who sneaks'; [ɕinobi]) was an infiltration agent, mercenary, or guerrilla warfare and later bodyguard expert in feudal Japan. They were often employed in siege, espionage missions, and military deception.[1] They often appear in the historical record during the Sengoku period,[2] although antecedents may have existed as early as the 12th century.[3][4]
During the Japan's warring state period, jizamurai clans of peasant-warriors in Iga Province and the adjacent Kōka District formed ikki – "revolts" or "leagues" – as a means of self-defense.
Following the Tokugawa shogunate in the 17th century, the ninja faded into obscurity.[5] A number of shinobi manuals, often based on Chinese military philosophy, were written in the 17th and 18th centuries, most notably the Bansenshūkai (1676).[6]
Ninja is the on'yomi (Early Middle Chinese–influenced) the two kanji "忍者". In the native kun'yomi reading, it is pronounced shinobi, a shortened form of shinobi-no-mono (忍びの者).[7] The word shinobi appears in the written record as far back as the late 8th century in poems in the Man'yōshū.[8][9] The underlying connotation of shinobi (忍) means "to steal away; to hide" and—by extension—"to forbear", hence its association with stealth and invisibility. Mono (者) means "a person".[citation needed] The word ninja was uncommon, and a variety of regional colloquialisms evolved to describe what would later be dubbed ninja.[5] The first known English use of the word ninja was in 1964.[10] Kunoichi (くノ一) is, originally, an argot which means "woman";[11]: p168 it supposedly comes from the characters くノ一 (respectively hiragana ku, katakana no and kanji ichi), which make up the form of kanji for "woman" (女).[11]: p168 In fiction written in the modern era kunoichi means "female ninja".[11]: p167
By the time of the Meiji Restoration in 1868, shinobi had become a topic of popular culture in Japan which featured in many legend and folklore, where they were associated with many supernatural abilitiles.