A priority certificate provides official proof of a patent application in Japan. This request can be made by filling out and submitting a form, along with a small fee. The form needs to be submitted in Japanese.
However, it is also possible to obtain proof of a patent in Japan free of charge though the Electronic Priority Document Exchange program (PDX). PDX is an electronic system run by the World Intellectual Property Organization that provides priority documents to applicants without cost as long as the relevant patent office is a member of the PDX program. Furthermore, applications to PDX may be submitted in English.
If you have any questions about obtaining a patent in Japan please contact our office for a legal consultation.