Currently, in patent examination, when judging the inventiveness of a claimed invention, examiners often reject the inventiveness of a patent application by determining that "taking into account reference documents and common knowledge can achieve the technical solutions for which claims of the application seek to protect". However, neither the existing patent law nor related examination guidelines give a clear definition of common knowledge, thus causing disagreement between the applicant, agent, and examiners regarding "whether the technical solutions for which claims of the application seek to protect achieved by taking into account reference documents and common knowledge should be considered obvious".

With regard to how to respond to an official action involving common knowledge, I will discuss the following aspects, as a reference for you.

You first need to know what common knowledge is. Common knowledge is mentioned in Step 3 of the Three-step Approach for assessing inventiveness as set forth in Section 3.2.1, Chapter 4 (inventiveness), Part II of the Examination Guidelines: determining whether a claimed invention is obvious to a person skilled in the prior art, i.e. in the following circumstances, it is usually considered that the above technical teachings exist in the prior art : (1) the said distinguishing feature is common knowledge, such as a customary means in the art to solve the redetermined technical problem, or a technical means disclosed in a textbook or reference book to solve the redetermined technical problem. In addition, it is also mentioned, for instance, in Section 4.3 (Determination of Evidence) of Part IV (Examination of Requests for Reexamination and for Invalidation) of the Examination Guidelines, i.e. supplying evidence of common knowledge such as that in a technical dictionary, a technical manual, or a textbook well-known in the skilled art, to support the allegation of common knowledge in the decision of rejection and the interlocutory official action. From the provisions of the Examination Guidelines, we can conclude that common knowledge is the conventional means in the art and technical means solving technical problems disclosed in textbooks and reference books (dictionary or technical manuals). Common knowledge is accumulated through long-term research, production, use or life and has been widely recognized, and has been known or should have been known by all persons skilled in a related art; therefore, considering such features, if a technology feature has been considered common knowledge, the technical effects achieved through it default necessarily public known, then a technical solution containing such technical feature as a distinguishing feature is certainly obvious.

Following understanding of what common knowledge is, statements should be made as to the distinguishing technical features corresponding to common knowledge.

First, you can analyze and elaborate the prior art stated in an official action, i.e. documents of categories A, X and Y cited in the search report. These reference documents cited in the search report and the prior art represent advanced or representative technology (including the widely used or accepted technical solutions) in the technical field. Carefully read these reference documents, carry out analysis of such documents accordingly, and draw a conclusion favorable to the application documents.

To come to a corresponding conclusion, you need to carry out the following analysis:

First, you need to analyze whether the documents in the search report contain expressly or implied distinguishing technical features that the official action is against. Generally, if they are stated in documents retrieved by examiners, the official action often mentions such features; therefore, these documents usually do not record corresponding distinguishing technical features.

Second, analysis should be conducted to determine whether the technical solutions and designs stated in the prior art are largely the same. If so, the technical features stated in these prior art documents are likely to be conventional technical means in the technical field, and thereby can be determined as common knowledge in this field. I think one or two identical prior art technical solutions are not enough to prove that a technical solution is common knowledge, because common knowledge should be a technical solution that has been very widely accepted and has been known or should have been known by all persons skilled in a related art, and you cannot rely on one or two published patent documentations to determine that a technical solution is common knowledge in the field. Therefore, in order to clearly determine whether a technical feature stated above is common knowledge in the field, it is necessary to further search for the identical technical feature stated in the above existing technical documentations, to finally determine whether the technical feature stated in the existing technical documents is a conventional technical means in the technical field. If it is determined that the above existing technical feature stated in the existing technical documentations is common knowledge, you can directly argue that the distinguishing technical feature in the application is not common knowledge in the field obtained through the above analysis. If you are unable to clearly determine that the technical feature stated in the existing technical documentations is common knowledge, then you can carry out the following analysis.

Third, if the technical solution stated in these existing technical documentations or further retrieved existing technical documentations are not the same or mostly not the same, i.e. you cannot determine common knowledge in the field, then you can further state that the relevant technical problem in the field is solved by many different technical solutions, and that distinguishing technical feature considered common knowledge in the field is one of the solutions for the above relevant technical problem, so as to prove that the distinguishing technical feature that is considered common knowledge in official action is currently a different technical solution to the corresponding technical problem, thereby drawing a conclusion that the distinguishing technical feature identified in the official action is not common knowledge in the field.

Next, you should carry out detailed analysis of the technical problem to be solved by the distinguishing technical feature, and assess whether the reference document in the official action has made a statement or disclosure as to the solution to a corresponding technical problem. If the reference document and the technical problem to be solved by this application are different, then, apparently a person skilled in the art has no motive to obtain the appropriate technical solution, that is, the technical solution is not obvious to a person skilled in the art.

If the reference document and the technical problem to be solved by this application is identical, you need to further analyze the technical solution adopted by the reference document and the technical solution adopted by this application. If both the technical solutions adopted by the two are identical, then you need to further analyze technical effects stated in the technical solution in the reference document and technical effects stated in the technical solution in this application. Typically, an applicant usually clearly sets out technical effects corresponding to inventive points in the description; therefore, by comparing the technical effects stated in respective technical solutions of the reference document and of this application, you can clearly ascertain whether the reference document has given technical teaching as brought by the relevant distinguishing technical feature. If the technical effect achieved by the reference document is completely different from that of this application, then it is obvious that a person skilled in the art will not obtain the relevant technical teaching from the reference document to combine with a distinguishing technical feature for the purpose of technical solution of this application.

Therefore, in the course of the argument, you must clearly state your views, i.e. the distinguishing technical feature in an official action is not common knowledge and, on the basis of reference documents, a person skilled in the art could not obtain the appropriate motivation/teaching to improve the reference document in order to obtain the technical solution to be protected.

In addition, according to the Examination Guidelines, the common knowledge in the art cited by examiners in an official action notice should be definitive. If the applicant objects to the common knowledge, the examiners should provide justification or evidence to prove it. So, in the process of response, you may also request examiners to provide evidence concerning common knowledge.

This article is an analysis and discussion of common knowledge in assessing inventiveness, and I hope that it can help applicants and patent agents respond to official actions.