Are "forehead protectors" historically accurate?
 

So after reading the latest issue of Shredder in Hell, it hit me that several characters are wearing forehead protectors in IDW, headbands with metal plates. The Savate wore them, most of the Foot Clan starting with #42 wears them and that Demon Kid wears one.

What I wonder is if it's actually a thing ninja wore? I know TMNT is hardly unique in depicting them, several other pop culture depictions of ninja are shown with the forehead protectors such as Naruto and Kakuranger. However, I can't find any evidence or statement that it was a real thing. Attempting to google "ninja headband" either leads me to non-plated headbands or the ones from Naruto. I can only seem to find modern depictions of these things and no statements about the historicity.

So are they just a pop culture thing? I know TMNT and other modern depictions of ninja have a tendency to get the kunai and sai wrong, it's not exactly hard to imagine it's a creative liberty.

It's not a ninja thing, but the headbands are a real item.

Shinsengumi, a police force during the Bakumatsu period of Japan had them.

Huh, cool. I still wonder how they ended up on pop culture depictions of ninja though?
https://upload.wikimedia.org/wikiped...-Uniformen.jpg

headbands (Hachimaki) in general are a cultural thing in Japan. There's been ninja before having headbands, but Naruto probaly made it more "mainstream" outside of Japan with hachimaki with guards.