A list of the best Ninja Movies. In the United States, Ninja movies surged in popularity in the early 1980's and have been with us ever since. We believe we've thought of them all, but if you think we missed one feel free to add it to the list yourself. Ninjas were the covert agents of feudal Japan. They were assassins and spies. Ninjas date back to at least the 1300's, although the word "shinobi" (another word for ninja) did not begin to appear until the 1400's. Ninjutsu is an even later word. Since espionage was considered dishonorable in Japanese cultures, ninjas were shrouded in mystery to help keep their employers identities a secret. Ninjas have been used in popular culture for centuries, appearing in countless folktales. Today, Ninja Films continue that tradition.