10.4
I could technically have a bit of alcohol if I used magic to boost my kidney function.
The breakdown of alcohol happens entirely in the liver.
This is common knowledge where I'm from, and I thought everywhere. Is it not in Japan?
Might be something to consider localizing.
(The kidneys can't concentrate alcohol. Totally drunk, your blood might be 0.2% alcohol. One-fifth of one percent. At that 0.2% BAC, only 0.2% of what the kidneys remove will be alcohol. Basically nothing. Relying just on your kidneys, drinking a lot of water, you would get sober in a few weeks, maybe.)