Ninjitsu came from japan?

As far as most people who are educated on this subject are concerned, ninjitsu is an art that was created in the image of the Shinobi (correct term for the ninja). No one can prove that it is the original art of the ninja because there is very little information on them due to their way of life. Ninja were often members of the lower/lowest cast in Japan who carried out the dishonourable work such as spying, ination, and espionage. Because of this, war lords would not have kept records of their dealings with the ninja for fear of being accused of dishonourable conduct. Due to this there is very little information of the ninja, we know they existed, but beyond that we only know a bit about how they functioned. From descriptions of them in historical doents, we have an idea that they were often skilled in acrobatics very similar to what people practice in freerunning and parkour, dirty fighting, and camouflage. Anything beyond this is mostly speculation, and information taken from Chinese and Japanese legends and myths.