Divisional patent applications can be used to secure additional patent protection on patent applications already on file with the JPO and which may cause concern with your clients’ competitors when issued as patents. You and your clients should consider filing a divisional application in Japan in the following cases:

1. Anyone can file an opposition within six months from the date of publication in the Japanese Official Gazette (in Japan, after issuance of a certificate of patent, the patent is then published in the Japanese Official Gazette at a later time). When a request for opposition is filed, the period for filing a divisional application will already be over. Therefore, in cases that are likely to be opposed, file a divisional application upon issuance of a Notice of Allowance.

   We also recommend filing a divisional application in the following scenarios:
   – when the invention is being used or is about to be used;
   – when a third-party submission has been filed to deny its patentability;
   – when a request to inspect the file wrapper has been filed with the JPO.

2. If a patent is granted in other countries and the inventions in the granted claims have a different technical feature from the claims in Japan, file a divisional application with the granted claims. The Patent Prosecution Highway (PPH) program can be used at the same time to quickly allow the divisional application.
3. If a divisional application was filed in other countries, or if a continuation application was filed in the US, and if the inventions disclosed in such applications have a different technical feature from the claims in Japan, file a divisional application with the same claims as such foreign applications.
4. If you would like to pursue any canceled claims, file a divisional application with the cancelled claims.
5. If there are embodiments not covered by the present claims, file a divisional application with claims corresponding to these embodiments.
6. If the application is granted without receiving a Notification of Reasons for Rejection due to lack of novelty and inventive steps, file a divisional application so that there is a chance to seek broader claim coverage.
7. If you would like more time to consider the scope of claims, file a divisional application.

For when a divisional patent application may be filed, please see:

https://www.ondatechno.com/en/faq/patent/p345/