A first filing in Japan is required only if the invention was completed in Japan and it potentially falls within one of the 25 sensitive technology categories designated for national security purposes.
If the invention was completed outside Japan, or it does not fall within those categories, there is no requirement to first file in Japan.

No. The inventor’s nationality is not decisive. The determining factor is where the inventive concept was finalized.
If the invention was completed outside Japan, the application may be filed first in another country, even if one or more inventors are Japanese nationals.

It refers to the location where the essential technical idea of the invention was established.
For example, if the key inventive step was developed in research activities conducted in Japan, the invention is considered completed in Japan.

Yes. If an invention is conceived or completed in Japan, or arises from collaboration with a Japanese company or research institution, the first filing requirement applies regardless of the applicant’s nationality or place of incorporation.

Filing abroad before filing in Japan may constitute a violation of Japanese regulations and can result in penalties, including fines or imprisonment.

If the application is not required to be first filed in Japan, obtaining a foreign filing license under Japanese law is not necessary.