According to the draft amendment, real estate buyers, including Japanese nationals, will be required to state their nationality on the registration application form and attach a supporting document, such as a copy of their passport or residence certificate.
While the obligation will not apply to already registered properties, nationality information may be registered upon request.
For privacy reasons, the provided nationality information will not be shown in the real estate registries and will not be disclosed to the public.

AloJapan.com