Is 忍者/忍び also used for women?

Question

I was discussing with a friend, who asked me if 忍者 is also used for women, or if くノ一 is used/preferred. I know 者 means "person", so it seems to be neutral; and Weblio defines the word using 者, which again seems to suggest it can be used for women; but I noticed in Basilisk female characters are called 女忍者.

I wasn't able to find something definite about this: can 忍者 be used for women, or does it sound strange/wrong?

Edit: Another friend of mine said that 忍び is used for men, but weblio doesn't say anithing about that, and it being an abbreviation for 忍びの者 it does seem neutral; not sure if it can also be used for women.

Answer 1

I hate to sound realistic here, but the concept of the female ninja is basically all fictional to begin with. If I am not mistaken (which I do not think I am), there exists no record so far that proves the existence of a female ninja in real life that performed the same tasks as a male ninja such as surveillance and destruction.

That being said, the word 「忍者{にんじゃ}」 can technically refer to both male and female ninjas in fiction, but when the gender is of importance to the story, the words 「女忍者{おんなにんじゃ}」 and 「[くノ一]{くのいち}」 are often used.

The word 「くノ一」 itself is as old as you expect a Japanese word to be, but it has only been several decades since it started to be used to refer to a female ninja in fiction. Before that, 「くノ一」 was only a slang word for 「女」.

「く」, 「ノ」 and 「一」 are the components/strokes of the kanji 「女」. That is in the correct stroke order, too.

In conclusion, 「忍者」, 「忍{しの}び」 and 「忍びの者{もの}」 are all gender-neutral. If the author sees it fit, however, s/he will use 「女忍者」 or 「くノ一」 to refer to a female ninja in fiction.