For biological and chemical applications, the Applicant may hope to file two or more divisional applications based on the parent application. Sometimes, due to that the deadline for filing divisional applications is approaching and the claim set for the divisional applications could not be well confirmed and prepared, the Applicant may want to first file these divisional applications with the same claim set, and then make further amendments to the claims for each divisional application via subsequent voluntary amendments when requesting the substantive examination or within three months after receipt of the Notification of Entry into Substantive Examination Stage.  However, the Applicant may concern whether double-patenting issue will be raised by the Examiner during the filing stage and preliminary examination stage of these divisional applications.

As for double-patenting issue, in Part II, Chapter 3, Section 6.2.1.1 of the Guidelines for Patent Examination, it prescribes the method of handling of two applications for an identical invention-creation filed by the same applicant as follows:

Where, during examination, it is found that the same applicant has filed two patent applications for an identical invention-creation on the same day (the date of filing, or the priority date where priority is claimed), and these two applications have met all the other conditions for patentability, the examiner shall notify the applicant of making a choice or amendments with respect to the two applications respectively. 

From the above provisions, it can be seen the double-patenting issue is generally raised when the application is intended to be granted a patent right.  Therefore, the Application does not need to consider double-patenting issue during the filing stage and preliminary examination stage of these divisional applications.

Nevertheless, according to the provisions of Article 2.2 in Announcement NO. 411 issued by the China National Intellectual Property Administration (CNIPA), filing multiple patent applications at the same time or successively with the contents of invention-creation obviously identical may be considered as abnormal patent-filing behaviors.  Therefore, in order to avoid unnecessary query from the CNIPA, we would like to suggest the Applicant considering filing two or more divisional applications with different claim sets.