Ninjutsu (忍術): Traditional Japanese art of stealth, camouflage, and sabotage, developed in feudal times for espionage and now practiced as a martial art.
Ninjutsu Art is wide known from Sensei Hatsumi (Bujinkan), Sensei Tanemura (Genbukan), Sensei Tanaka (Jinenkan) all from Iga Region.
There are still a few Ryus (Schools) from the Koga region also. Just have to search...