u/katsumi-sama

Is it true that if you don’t take summer classes, you have to leave Japan for the entire summer?
And if you do take summer classes, you have to pay extra tuition for them? I read about this while doing a research about the university, however I’ve also seen comments that claim there’s no such a thing and it should be a misunderstanding, so I’m confused. Can TUJ students confirm if this is legit or not? It just makes no sense to me.