[["A ninja was a person trained in ancient Japanese martial arts and employed especially for espionage and assassinations.\n\nNinjas originated in the mountains of Japan over 800 years ago as practitioners of ninjutsu, a martial art sometimes called \"the art of stealth\" or \"the art of invisibility.\"", 1942.0], ["A ninja or shinobi was a covert agent or mercenary in feudal Japan. The functions of a ninja included espionage, deception, and surprise attacks. Their covert methods of waging warfare were deemed dishonorable and beneath the honor of the samurai.", 1605.0]]
what is a ninja
naruto,ninjas