Understanding Japan’s Unique Divisional Application System

The JPO (Japanese Patent Office) does not have an RCE (Request For Continued Examination) system as the means against a final such as exists at the USPTO and KIPO South Korea PTO. In fact, there is no Continuing Application system at the JPO like in the US. Therefore, when a decision of refusal issued, it is necessary to submit remarks with an Amendment to refute. In addition, in the case of a Final Office Action (Decision of Refusal), there is no choice but to request an Appeal. Therefore, when compared to the US system, the options for responding to a Final Office Action in Japan may seem to afford the applicant less protection. 

However, I believe that the rate of patents granted on Appeal at the JPO is higher than that of the other PTO’s: the hearing in the course of an Appeal is basically very flexible and also favorable for the applicant. Regarding the Appeal cases at our firm, the rate of successfully obtaining patents is over 95%.  

At the time of filing an Appeal, it is possible to amend the claims and specification. Furthermore, after the examination is processed, if the Board of appeal gives a notice of refusal, the applicant may file an amendment to the claims and specification. Therefore, in general, and if well understood, we feel that the Japanese Appeal system is very user friendly: it can be likened to the “second battlefield with hope” for an applicant following the examination.

However, since the same cost as the examination stage is again incurred in the appeal stage, most large Japanese companies typically do not file Appeals. Rather, they focus on seeking to obtain patents in the examination stage. Therefore, it’s with this background that the divisional application system is used: see Article 44 of Japanese Patent Law. In the case of the US, divisional applications are used as a means of resolving “Restriction Requirements” but in the case of Japan it is a more flexible system for the applicant.

The concept of “divisional application” itself is the same in each country, and the point is that “the invention being disclosed in the original application could be extracted and the right is granted in a new application”. The merit of the divisional application in Japanese practice is that when it is rejected (including “decision of refusal” i.e. Final Office Action), the inventions that you want to dispute with JPO are left in the original application and refuted by a written opinion / amendment, and the inventions which are not included in the reasons for rejection could be filed in the divisional application separately.

The point of a “Successful divisional application” is “obtaining retroactive effect” (Patent Law, Article 44, Paragraph 3). That is, if the division is properly performed, it is treated as if “the divisional application was filed at the time of the original application” in the examination. If this retroactive effect cannot be obtained due to an improper division, the application is filed on the actual filing date of the division, and the benefits of the original filing date cannot be enjoyed. Therefore, the essential issue is how to get it recognized as a proper division. This treatment is the same as those of the divisional application systems in foreign countries.

Regarding this point, there are detailed descriptions in the “Patent Examination Standards” issued by the JPO. In summary, the point is simply to “clearly assert and prove that the new claims of the divisional application and the necessary changes made on the specification are within the scope of the original application.” This is originally derived from the idea that “divisional application is a kind of amendment”. As a matter of course, filing a divisional application beyond the scope of disclosure of the original application is contrary to the purpose of the patent system, as is the case of the additional amendment of new matters.

As a Japanese Patent Law procedure, in principle, the divisional application could be “filed at the time or time when amendment is possible” (Patent Law Article 44), but it can be divided at other times by revision of the law, for example, 30 days from the decision of a grant.

The essential point regarding the documents to be submitted, is how to prepare the divisional application specification and the required “Written Statement”. In conclusion, it seems appropriate to describe only the divisional matters in the specification of the divisional application, and submit the amendment separately with the points associated with divisional matters. 

Also, note that “Multi-Generational Division” is possible. “Multi-Generational Division” means that a divisional application is further divided multiple times. In this regard the Patent Examination Guideline states that “if a certain application is divided and further divided, a division over two generations will be established”. “When the first generation divisional application and between the second generation and the third generation are satisfied, the third generation divisional application will be filed at the filing date of the original application. It is stated that it will be retroactive”.

Again, there is no Continuing Application system at JPO like in the US. The divisional application strategy is very effective in Japan for forming a “patent portfolio” to protect the company’s technology with a large number of patents. For that purpose, as a matter of course, it is important to strategically enhance the items described in the specification of the original application, and to extract and prepare the invention which could be extracted when a divisional application is filed in advance, while also confirming the accompanying application of any competitor.


By Takaaki Kimura

Managing Partner and Patent Attorney with over thirty-five years of IP law experience.