I came to Japan recently, and want to use your computer system.

We assume you are talking about Export Trade Control.
If you are employed at any organization in Japan and paid, you do not need go through any procedures.
Even if you are not employed but just staying (such as a student), if you have already gone through the export trade control procedure at your institute, you would not need to do anything. You would need to go through this procedure only when

1. You are in Japan but not employed by any institutes, and
2. You have been in Japan for less than 183 days, and
3. You have not gone through the export trade control procedure yet.

If you meet all three criteria above, please read the notes below.
If you do not meet any of the above three criteria, you do not need to read below.
Just go ahead and prepare your science application form for each of the computing facilities(such as for the supercomputer).

(In case you meet all the three criteria above, read it)
In Japan, there is a legal regulation called "Export Trade Control Order."
According to this regulation, when an applicant to our computer system does not have the Japanese nationality, and if he/she is not officially employed (based on a written contract) by institutions in Japan or when he/she has not stayed in Japan for more than six months, NAOJ or other institute in Japan has to prepare and submit a set of specific documents for the export trade control to Ministry of Economy, Trade and Industry.
This is for proving that there would be no problem for the applicant to become a user of our computer systems.
The applicant is supposed to give us necessary information for us to get the paperwork done, and this has to be completed before actual science review begins.
Please take a look at our webpage for this purpose for more details.
(Last updated 2024 or before)