How can you prove your address

When you get a real estate, you have to prove your address to register your name and address.

In case you live in Japan, you can get a certificate  of address (Juminhyo) from a local government. You should take care that there is no Social Security number (In Japanese MY NUMBER)  in this ducument. 

In case you do not live in Japan, how can you prove your address?

 Like this case, you have to prepare the ducument from your government-related organization. If you are American in HK, you can get this document at the American embassy in HK. For real estate registration, Japanese language is only accepted. That means , alphabet is not accepted. So you have to transrate your information to Japanese 'KATAKANA'.