I had a hunch, a tingle if you will, when reading the earlier chapters. This TCG arc is some business ad, marketing shenanigans from college! THIS MANGA IS AN INDERECT BUSINESS AD CURICULLUM!
don't consuming some chocolates cause acne? Tho even without selling the 'solution', i'm sure some skincare/soaps would be popular too if it's not already popular/common versus cleaning magic
From what I am given to understand, Chocolate doesn't really cause acne; a near-complete lack of Body and Armpit Odor causes younger Japanese people to shower, on average, about once or twice a week... and you would obviously have acne if your entire society mocked those who "need" to shower once a day.
Yes, bathing is a thing, but it's still done less frequently.
[EDIT] It seems this may have changed since my family lived there, and that body-washing has become more of a daily thing more recently; I forget that Im old, cos my mom's whole family lived in Japan.... from 1965-80; and that's been a minute.
A huge portion of belief about the human body in Japanese culture is literally just wild superstition, and a lot of Japanese people will try to do anything to pretend science is wrong or just doesnt apply to Japanese people; women can't walk during pregnancy, chocolate causes acne, boys "automatically" Rape girls if left alone and are not responsible for doing so, and other stuff that makes perfect sense in a medieval society... Which japan kinda still is in a LOT of ways, honestly.
It's not bad, but it's true
Also, what idiot would get a book for a Member Of Royalty, and then hang on to it for days and fuck off all over town with it?
The entire premise of the Moon Gate and Red Potions on Earth is more believable than that!