Ninjas originated from China. The practice of stealth and espionage, which are key characteristics of ninjas, can be traced back to ancient China. The Chinese martial arts and tactics heavily influenced the development of ninjutsu, the art of the ninja. While ninjas are often associated with Japan, their origins can be traced back to China where they were known as "shinobi" or "shenobi." Over time, the practice of ninjutsu spread to Japan and became an integral part of Japanese history and culture.