According to the "tag what you see" policy, should we tag Ninja only when a character looks like one? post #858853, post #346732. And not when the background say they are, like so much Naruto?

Yes, only tag ninja when they look like a ninja.

Of course defining what a ninja looks like is by definition almost impossible, how do we define this tag?

We'd probably just use rough guidelines on things that would be notable as making the outfit/depiction ninja-ish. Defining what is and isn't one is a similar issue with defining say a pirate, vampire, or several other class/race tags.

ion288 said:
Of course defining what a ninja looks like is by definition almost impossible, how do we define this tag?

A feudal era peasant farmer. Seriously though I think we all know what a stereotypical ninja looks like, so if they look like that tag it.

I'd say it's sufficient if they are equipped with a reasonable number of features that have since become stereotypical (though in most cases apocryphal) ninja equipment: shuriken; kunai; armored headband and/or bracers; mask over lower face; fishnet leggings, gloves, or bodysuit; wrist wraps and/or ankle wraps; short kimono, etc...

Also we do tag what we see, and in itself it won't be sufficient, but if the character is considered canonically a ninja in their fictional universe, that should also be taken into consideration in borderline cases.