Answers (2)
Gian,
Contrary to popular belief, Ninjutsu is not a "martial art," though it does contain some disciplines within the umbrella-term that westerners call "Ninjutsu".
Ninjutsu is a western-term. Hollywood expanded on this notion (and other countries ran with it too--including some in Japan).
Ninjutsu is actually called "Shinobi-no-jutsu". A practioner of Shinobi-no-jutsu is called a Shinobi-no-mono (or simply a "Shinobi".)
Shinobi-no-jutsu was and is a collection of disciplines that were grouped under a single term. Again, that term is "Shinobi-no-jutsu". Shinobi-no-jutsu includes espionage (it's priority discipline), sabotage, and assassination. Though, espionage (spy-craft) is the reason the Shinobi came into existence.
Unlike popular culture's opinion, Shinobi didn't come from the peasant population too often. More often than not, Shinobi were of the Samurai-class.
Much more could be said about this topic.
Pardon me, Gian, I accidentally left-off something when I wrote you this morning. I said,"Contrary to popular belief, Ninjutsu is not a "martial art," though it does contain some disciplines within the umbrella-term that westerners call 'Ninjutsu'". I meant to say, "Contrary to popular belief, Ninjutsu is not a 'martial art,' though it does contain some martial disciplines within the umbrella-term that westerners call 'Ninjutsu'".