The modern fascination with the ninja, the black-clad warrior-assassins who arrive in the night to bring expert fighting, often obscures who the ninja were.
During the chaos of the late medieval period in Japan, they emerged as a new class of warrior, half-agent, half-soldier.
They were rarely called ninja in Japan (although the word was known) but rather shinobi, meaning “one who steals away” and this reflects that they were a secretive type of warrior designed to act quickly and with surprise.
A ninja was involved in many actions related to the turbulent times in which they lived. They functioned in a mix of roles, as spies, saboteurs, assassins and guerrilla fighters.
There were women who served as ninja, and were called kunoichi; their work was principally as spies. The most notable of these was the Lady Chiyome, who set up an army of female spies in 16th-century Japan.
Ninja were regarded with contempt by the samurai, both because of the lack of observation of their bushidō code and their generally lower social status and secretive nature.
The ninja remained active until the Tokugawa shogunate restored order in Japan, after which they became less necessary because of the improved stability within the country.