Japanese people consider the ninja as spies not warriors. In Japan ninjas are called shinobi.
Ninja means the one who endures, shinobi means the one who conceals himself.
You cannot be a ninja by training, the tradition of ninja is passed from generation to generation.
There are 2 main ninja clans in Japan: Iga and Koka. The town of Iga is in Mie, about an hour long car-ride from this museum. The name of Iga city will soon be changed into the Ninja city.
The ninja were trained by practicing long distance running, disguise techniques, climbing, gun powder trsining and the botanics.
A number of samurai commanders were targeted by ninja. Uesigi Kenshin, a famous daimyo of the Kanto area during the Sengoku period, was killed by a ninja sent by Nobunaga. Nobunaga himself once shot by a ninja.
A ninja should not be heavier than 60kgs in order to run fast.
The ninja usually wore ordinary clothes to blend in or the navy blue colored outfit since it is more difficult to notice them in the moonlight.
The ninja did not eat meat while on the mission to not to leave any body odor behind.