
Doesn't have anything to do with japan, yes they could have changed the age but in historical times, that age gap was common and many girls were married off at a young age even to middle aged men. Seeing how they have a lot of real historcal facts in the manga, I guess they wanted to keep it "realictic" on how it actually was at that time so hence the age gap

I 100 % get what u mean, it leaves a very uncomfortable feeling seeing it like that but seeing it has borderline "healthy" how they tried to make it helps a bit when u gaslight urself into thinking that she was married off and they developed a "friendship" first and mybe hope that they didn't do anything until she was an adult XD
A 9 year old and a 20 year old! Why japan why????