anime history - When & where did the unnatural hair color aka You gotta have blue hair trope originate? - Anime & Manga Stack Exchange

I specifically want to know which manga or anime started the trend, so I can reason from there to the how question, in order to not make general assumptions. There was a time in manga/anime where

Does the colour of the hair of the character always mean the same or some anime and manga made their own rules? - Quora

Curtains Match the Window - TV Tropes

Did the trope of 'You Gotta Have Blue Hair' originate in anime and manga, or can it be seen in enough older works to determine a different origin? Is there any official

Anime & Manga / Yandere - TV Tropes

tropes - Why do many characters tend to have crazy hair colors and styles? - Anime & Manga Stack Exchange

Why is it that anime characters are often drawn with unnatural hair colors? (pink, red, blue, and similar bright colors)? - Quora

HOLiC (Manga) - TV Tropes

Did the trope of 'You Gotta Have Blue Hair' originate in anime and manga, or can it be seen in enough older works to determine a different origin? Is there any official

Fruits Basket (Manga) - TV Tropes

anime history - When & where did the unnatural hair color aka You gotta have blue hair trope originate? - Anime & Manga Stack Exchange

Did the trope of 'You Gotta Have Blue Hair' originate in anime and manga, or can it be seen in enough older works to determine a different origin? Is there any official

Anime Hair Colors: Do They Carry Any Significant Meaning In Japanese Culture?

Why is it that anime characters are often drawn with unnatural hair colors? (pink, red, blue, and similar bright colors)? - Quora

Anime Hair Colors: Do They Carry Any Significant Meaning In Japanese Culture?