Where a patent application (parent application) contains two or more inventions, utility models or designs, the applicant can submit a divisional application at its own initiative or upon notice given by the China Patent Authority. For a patent application which obviously lacks unity, Chinese examiners will directly conduct a search and examination of a set of claims including Claim 1, provide their opinion on these claims and notify the patent applicant of the defects that result in a lack of unity. At the same time, Chinese examiners will remind the patent applicant that deletion of the said set of claims on which search has been conducted and comments rendered while retaining other claims which do not have unity with said set of claims and for which no search has been conducted would render the patent application non-compliant with Rule 51(3) of the Implementing Regulations of the PRC Patent Law, and would thus result in rejection of the application.  For this reason, it is suggested that key inventions be placed in the first set of claims. 

Rule 42 of the Implementing Regulations of the Patent Law states that an applicant can file a divisional application before the registration deadline; however, where a patent application has been rejected, withdrawn or deemed to have been withdrawn, no divisional application may be filed. More specifically, under the Chinese patent system, a divisional application may be filed (1) at any time before a decision for the parent application is issued (i.e., during the formal examination and substantive examination stages), (2) no later than two months after receiving a Notice of Allowance on the parent application, (3) within three months of receiving a decision rejecting the parent application, (4) after a request for re-examination of the parent application is filed, (5) within three months of receiving a re-examination decision rejecting the parent application, or (6) during an administrative suit against a re-examination decision of rejection of the parent application.

Given the above, where the above Implementing Regulations would restrict the applicant from voluntarily filing amendment to include claims that were excluded from search and examination due to the unity issue, an alternative recourse is to pursue such claims through a divisional application.  In another condition, the applicant will have an additional opportunity for voluntary amendment in response to an office action, where voluntary amendment would not be considered by the examiner for any reason, by way of a divisional application.  Alternatively, after the Patent Re-examination Committee has upheld the rejection of a patent application, the applicant may choose a divisional application to continue its patent prosecution in order to avoid being involved in administrative litigation.

In China, where an applicant would like to file another divisional application (a second or second-generation divisional application) from a first divisional application, the second divisional application should still be based on the examination prosecution of the original application. However, this will not apply where there is lack of unity in the first divisional application and where the review opinion by the examiner entitles the applicant to file a second divisional application in response.

In view of such special provisions in China for divisional applications, a thorough understanding of the inner workings of the divisional application procedures will help applicants optimize the process of patent planning and protection.