"Kawahara Asako was among several Aizu women determined to defend the castle against invaders. Their education had prepared these women for war. They received extensive combat training and were educated to be “equally skilled in the ways of the pen and the sword.” These warriors stand in a long tradition of women in Japan who joined battles alongside their male counterparts and immortalized themselves as Onna-Bugeisha, literally, “female martial arts masters.”
https://daily.jstor.org/onna-bugeisha-female-samurai-warriors-feudal-japan/