Hollywood and Japanese pop culture have propelled the exploits of the ninja around the world. It’s interesting to learn that real ninjas are actually far from what moviews show us. Here is an interesting article on the topic: https://www.bookmartialarts.com/news/what-you-need-to-know-about-ninjas-their-training. I’m thinking of starting training Ninjutsu; are there any practitioners here?
I was exposed to some ninjutsu training when I study a couple Koryu systems.
Ninjutsu was and is part of many koryu ( such as the Yagyu Shinkage Ryu and the tenshin shoden katori shinto ryu).
In modern day terms, ninjas were special ops intelligence operators and, at times, assassins.
Ninjutsu became a stand alone system ( rather than a subsystem) during the Tokugawa shogunate.