Before filing for patent or utility model protection in Japan, it is advisable to keep the patented material secret, or at least unpublished. If the material you wish to patent has already been published elsewhere, it will have lost its novelty and will no longer be patentable in Japan. However, an exception exists for material patented in other countries that fit specific criteria.
Under the Paris Convention for the Protection of Industrial Property, foreign patent holders from a signatory nation, or a member nation of the World Trade Organization, can apply to have their patent rights recognized in Japan through claiming a priority right. To claim this priority right, the applicant must identify the foreign patent at the time of filing with the Japanese Patent Office and must make the application within 16 months of the filing date for the foreign patent.
If you have any questions about patent law in Japan, please contact our office for a legal consultation.