Ninjas also known as shinobi, were covert agents or mercenaries of feudal Japan.
Ninjas were trained in ninjutsu – a collection of fundamental survivalist techniques that focus on unconventional warfare, sabotage, and espionage. Their techniques include skills like free-running, archery, disguise, and concealment.
Most sources indicate that the skills that became ninjutsu, began to develop between 600 to 900.
Most of their missions were secret so there are very few official documents detailing their activities. Their tools and methods were passed down for generations by word of mouth.
It is difficult to pin down the emergence of the first ninja — after all, people around the world have always used spies and assassins. Japanese folklore states that the ninja descended from a demon that was half man and half crow. However, it seems more likely that the ninja slowly evolved as an opposing force to their upper-class contemporaries, the samurai, in early feudal Japan.
The concept of the samurai began to emerge during the mid-Heian Period (794-1185). Sneaky ninja predecessors probably existed as far back as the late Heian Period too. However, the shinobi, as a specially trained group of mercenaries from the villages of Iga and Koga, only appeared in the 15th century – making them a good five hundred years younger than the samurai.
The earliest approach to ninja training was taken by particular families of samurai warriors who passed on their skills from father or master (sensei) to son. These became the famous ninja families and explain why certain localities established long traditions of producing the specialised warriors. From childhood, a future ninja would learn to ride, swim, and handle weapons of all kinds. From the 15th century AD, ninjas were being trained in special camps which might involve entire villages. Some schools became especially famous such as the Iga and Koga schools. As leaders did not want rivals copying their tactics, all training was done orally lest written records fall into the wrong hands.
The ninja were an important tool during the Sengoku Period (1467-1568), but also a destabilizing influence. When warlord Oda Nobunaga emerged as the strongest daimyo and began to reunite Japan in 1551–1582, he saw the ninja strongholds at Iga and Koga as a threat, but despite quickly defeating and co-opting the Koga ninja forces, Nobunaga had more trouble with Iga.
In the unrest of the Sengoku period, mercenaries and spies for hire became active in Iga Province and the adjacent area around the village of Kōga, and it is from these areas that much of the knowledge regarding the ninja is drawn. Following the unification of Japan under the Tokugawa shogunate in the 17th century, the ninja faded into obscurity. A number of shinobi manuals, often based on Chinese military philosophy, were written in the 17th and 18th centuries, most notably the Bansenshūkai (1676).
By the time of the Meiji Restoration (1868), shinobi had become a topic of popular imagination and mystery in Japan. Ninja figured prominently in legend and folklore, where they were associated with legendary abilities such as invisibility, walking on water and control over natural elements. As a consequence, their perception in popular culture is based more on such legends and folklore than on the covert actors of the Sengoku period.
Although no medieval texts actually describe in detail a ninja’s outfit, the most usual depiction in Japanese art from the early 19th century AD has them clad all in black. This would seem to be the most obvious colour choice because most of their work was done at night. It is also a convention of Japanese performance arts that a character wears black to show the audience that he or she is invisible.
The main weapon of a ninja was his sword or katana, perhaps a little shorter and less curved than those used by other warriors as a ninja might find himself in a restricted space like a narrow castle corridor.
An array of darts, spikes, knives, and sharp, star-shaped discs were known collectively as shuriken. While not exclusive to the ninja, they were an important part of the arsenal, where they could be thrown in any direction.
Superhuman or supernatural powers were often associated with the ninja. Some legends include flight, invisibility, shapeshifting, the ability to “split” into multiple bodies (bunshin), the summoning of animals (kuchiyose), and control over the five classical elements.
There is common misleading fact that ninjas were dishonorable – that was becouse evryone with good martial art skils could be ninja – so behind ninja cover could be honorable or dishonorable person – samurai were also ninjas when needed to.