How hard do you have to study in a JP Uni?

Hi there, if I will be going to Japan as a graduate student, how hard do I have to study in order to stay above the water, not getting into any academic trouble or academic probation? Do I have to get all C or up or I'm good as long as I take the classes no matter how well I do in these classes as a graduate student in accounting and finance?

Not all of the schools require your score in a previous school.
The fee differs in each school, the level that will be needed differs, too.
Also, if you are to enter as a normal student, I mean taking the same exam as Japanese do, you need to answer the test in Japanese (some Universities like public schools prepare exam in English).
Anyway, you need to decide which University do you want to go and ask them what you need. Most of the official sites have English pages. Some of their past exams can be purchased. Don't hesitate to make contact with the school.

Interesting question.
Ifd not really thought about the idea of going to university simply to pass the time and not get thrown out.
I am clearly behind the times in my thinking.