Where do ninjas train?

Ninjas were traditionally born into separate towns that were large groups of ninjas living together in clans. These groups were usually affiliated with a specific nearby leader. These villages are where the younger ninja would be trained at earlier ages through games and at older ages through martial training. Nowadays people who wish to learn the art of the ninja may go to camps or dojos throughout the worlds that teach ninjutsu, or ninpo. The best place to do this would be in Japan as it has been kept to its roots as closely as possible there.