Ninjutsu

A ninja (忍者^?) or shinobi (忍び^?) was a covert agent or mercenary of feudal Japan specializing in unorthodox arts of war. The functions of the ninja included espionage, sabotage,infiltration, and assassination, as well as open combat in certain situations. The ninja, using covert methods of waging war, were contrasted with the samurai, who had strict rules about honor and combat.