kawaiixsarang,
I only applied to the "research student", but I will try to answer your questions.
First of all, are you applying in the US? If you are, please go to the website of the consulate nearest you to find more information about deadlines etc. You can also download application forms there. There is also a guideline you can download, that will help you alot.
How do I retrieve an application form?
- consulate website or
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How do I send it (post office, FAX?)
-by post mail mail is fine. I think you can fax some items too.
How will I know if my application got accepted/rejected?
-they will either call you, or send you an email.
If I get accepted, when will the testing period begin?
-check your consulate. Its usually around the july~august.
How will they notify me if I do not pass/or pass the exams?
- phone call or email.
How difficult are the exams?? What should I work on to get a better chance of passing?
-according to the guidelines, there are 2 fields of study(social and humanity, or natural science), each will take certain exams. Please look at the guidelines for more info. Since it is also a competition, I'm just going to say that the exams are very hard. Your can look at sample exams at this website:
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Around what time of year will the interview be, if I do pass?
-check your consulate.
And from there... when will MEXT make the final decisions of who will get into the scholarship (around what time)??
-tentative selection is usually around early January. Final selection is mid-february.
How many Americans have been accepted as far as you guys know?
-From what I heard, only 1~2 is selected from the US. The undergraduate scholarship is dedicated to "developing" countries, US is not one of them.
There is about 9 months between application date and final selection, and the acceptance rate seems very low... so I would
strongly advise you to have a back up plan.