Ninja were professional spies during the age of the samurai. Their origins go back to the twelfth century, when the samurai class began to gain power. When the scale of fighting increased in the fourteenth century, it became necessary to conduct espionage activities against enemy forces, and ninja became even 더 많이 active.

Ninja were called upon 의해 their feudal lords to gather information, plunder the enemy's 음식 and weapon supplies, and lead the way in nighttime attacks. They received specialized training and were given special duties. Ninja remained active until the beginning of the Edo period...