raku-japanese-designed:

Japanese Word Today – Kunoichi くノ一

Kunoichi (くノ一) is the term for a female ninja or practitioner of ninjutsu (ninpo).
The term is thought to derive from the names of characters that resemble the three strokes in the kanji character for woman (女 onna); said in the order they are written: ku (く) – no (ノ) – ichi (一). Early literary quotes include Enshū Senkuzuke Narabi Nihyaku In (遠舟千句附并百韵) (1680) as well as Maekuzukeshū (前句付集) (1716), which specifically associates the word with the kanji 女 supporting the etymology of being overpowered.