How long have ninjas existed and what did they do? Although the ninja originated in Japan and is now known as NINJA around the world, few people know for sure. However, recent empirical research has revealed a different image of the ninja from that of the past. The ninja may have an image of wearing black, throwing shurikens and disappearing with a droning sound, but these are false images that were created later.
The most important duty of the ninja was to gather information and convey it to the lord. And the ninjutsu used by the ninja were not techniques for disappearing or fighting, but for survival, which were condensed with the most advanced technology of the time. If we apply modern classification to it, it can be categorized as medicine, pharmacology, biology, agriculture, meteorology, astronomy, mathematics, psychology, etc. However, it was the ninja who synthesized various knowledge and put it into practice, not as separate and decentralized things. It is from the books on ninjutsu, which were considered secrets, that we can collectively learn what “science” was like in those days, and I think this is extremely valuable.
It can be confirmed that ninja existed in various regions from the period of the Northern and Southern Dynasties in the early 14th century to the end of the Edo period in the late 19th century. Among them, the Iga and Koka ninja were excellent and were hired by the feudal lords and various domains. During the Warring States period, the ninja invaded enemy territory and castles to gather information, and sometimes disturbed or set fires. When the peaceful Edo period came, the ninja lived in castle towns as samurai and were involved in maintaining public order, and sometimes were ordered by the feudal lords to go to remote areas to explore.
The ninjutsu used by the ninja was not an outlandish or mysterious art, but rather a way of judging the weather and direction by sharpening the five senses without the use of equipment, searching for the presence of enemies based on the flight of birds, and learning how to use the body by imitating the movements of animals. I think it can be said that this way of life is a wisdom born from Shugendo, military books, and rules of experience. Although such ninjutsu was passed down from parent to child, it was often the case that important information was passed on orally, and not shared with others.
