Ok, first of all, according to your supplementary information, your application is a "wish" in Japan, that is, the school is mainly helping you to review, so in theory, the school will return your important materials. However, it's a bit worrying to press the phrase "after the wish, it depends on human effort", but Japanese schools and Japanese people are not very mechanical and bureaucratic, and will definitely analyze them according to specific circumstances. Don't worry about not returning them. They're not idiots either.

As an applicant, I suggest you call directly to ask, because it may be more troublesome to handle all the application materials in a unified way after the school has written it, so it is necessary for you to ask in person.

-

"University graduation certificate" refers to the final graduation certificate, which is one of the necessary materials submitted to the immigration bureau in the area where the school is located. Don't worry about returning it after passing the 100% review.

"Japanese proficiency certificate" refers to the materials about Japanese learning and achievements submitted by the applicant students. Theoretically, it is enough to have Japanese international test scores recognized by Japan, such as International Japanese Proficiency Test /j-test/nat. As long as you have grades, you can submit your transcripts together. The requirement of the Immigration Bureau is that only a copy is required for the audit, so if the school insists, it can only look at it unilaterally, and in theory, it will return 100%.