
Mochizuki Chiyome was a noblewoman in the 16th century who created an all-female ninja empire.
Chiyome was married to a samurai warlord who was killed in battle in 1575.
Chiyome then took an opportunity to recruit and train women to become ninjas!
It is probably important to note that during this time ninjas were not the mythical characters we know of today. The art of this profession was typically passed downfrom generation to generation and even though it was difficult and and an insane amount of skill was required to do the job well, the ninja career was not a prestigious one (unlike the samurais and political figures they occasionally assassinated).
However, Chiyome decided to play by her own rules and recruited her ninja students by seeking out orphans, criminals, prostitutes and the like. (She basically followed the Night’s Watch recruitment strategy.)
Her students were taught the way of the Shinto (female shaman), as well as how to become expert information gatherers, messengers, verifiers, and assassins.
What gave Chiyome’s ninjas the edge was that they were able to use their patriarchal society to their advantage and they played up gender roles to help stay undetected. Chiyome’s ninjas learned the art of seduction and would pose as geishas, prostitutes, or even actresses. They sharpened their lady’s fans creating a weapon for assassinations and dipped their hairpins in poison. However, the typical ninja toolkit was still used by Chiyome’s ninja’s, as well (projectiles, steal claws, binding powder and an obi).

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These ladies also had to learn to hold their breath for an obscene amount of time, balance on tree branches without making a sound, and dislocate their joints so they could free themselves in the unfortunate event that they were captured and tied up.
It is no wonder Chiyome’s ninja service was immensely popular.