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A concise comparison of inventive step assessment between CNIPA and EPO

Date: 26 July 2023

Inventive step is a crucial aspect of patent applications, as it distinguishes an invention from mere “add-up” of existing technology. The assessment of inventive step varies across different jurisdictions. Effectively assessing inventive step lies in objectively measuring the technical contribution of an invention, ensuring that the granted patent reflects the genuine value added by the inventor to the existing knowledge.


This article provides a brief comparison between the Chinese Patent Office (CNIPA) and the European Patent Office (EPO) regarding the assessment of inventive step in patent applications.


1. Legal basis for inventive step


The legal basis for assessing inventive step in front of CNIPA is primarily found in the Patent Law of the People's Republic of China (中华人民共和国专利法) and the Guidelines for examination in the CNIPA (专利审查指南).


Article 22(3) of the Chinese Patent Law proscribes that:


“inventive step means that the invention has distinctive substantial features and significant progress compared with the prior art”.


“distinctive substantial features” is defined in part 2, chapter 4, section 2.2 of the Guidelines for examination as follows:


  • “for those skilled in the relevant technical field, the invention is not obvious compared to the prior art. If the invention can be obtained by those skilled in the art through merely logical analysis, reasoning, or limited time of experiments based on the prior art, then the invention is considered obvious and does not possess significant substantial features”.


For the EPO, the fundamental principles for evaluating inventive step in patent applications are rooted in the European Patent Convention (EPC). Specifically, Article 56 of the EPC sets forth the key requirement for an inventive step, stating that:


  • “An invention shall be considered as involving an inventive step if, having regard to the state of the art, it is not obvious to a person skilled in the art”.


To put it briefly, the concept of "not obvious" plays a vital role in determining inventive step within the framework of both the CINPA and the EPO.


2. Definition of the skilled person


In many patent laws, the concept of "a person skilled in the art" serves as a significant basis for evaluating inventive step. This hypothetical individual plays a central role in various processes such as patent prosecution and litigation.


Part 2, Chapter 4, section 2.4 of the Guidelines for examination in CNIPA defines the person skilled in that art as “a hypothetical "person who is assumed to know all the ordinary technical knowledge in the art to which the invention belongs prior to the filing date or priority date, to have access to all prior art in the field, and to have the ability to apply conventional experimental means prior to that date. However, he does not have the ability to create. If the technical problem to be solved would lead the person skilled in the art to search for technical means in other technical fields, he shall also have the ability to acquire general technical knowledge and conventional means of experimentation prior to the date of the application or the priority date from the other technical field. The Guidelines add that “the purpose of setting this concept is to unify the standard of examination and to avoid the subjective influence of examiners as much as possible.

Turning to the EPO, Part G, Chapter VII, Section 3 of the Guidelines for examination in the EPO defines "the person skilled in the art" as someone in the relevant field of technology who is possessed of average knowledge and ability (average skilled person). The person skilled in the art is aware of what was common general knowledge in the art at the relevant date. The skilled person is also presumed to have had access to everything in the "state of the art", in particular the documents cited in the search report, and to have been in possession of the means and capacity for routine work and experimentation which are normal for the field of technology in question. If the problem prompts the person skilled in the art to seek its solution in another technical field, the specialist in that field is the person qualified to solve the problem”. “The skilled person may be expected to look for suggestions in neighbouring and general technical fields or even in remote technical fields, if prompted to do so. Assessment of whether the solution involves an inventive step must therefore be based on that specialist's knowledge and ability”.


Insofar, both CNIPA and EPO share similar definition of the skilled person, who possesses common general knowledge in the art at the relevant date and is able to find solutions in neighrouring field when prompted. However, a notable difference exists in that the EPO also takes into account the possibility of considering a group of individuals, such as a research or production team, instead of a single person, as the person skilled in the art. It is important to borne in mind that the skilled person maintains a consistent level of expertise when assessing inventive step and sufficient disclosure.


3. Comparison of assessment approach


CNIPA follows a three-step approach to assess inventive step which is elaborated in Part 2, Chapter 4, Section of the Guidelines for examination. Similarly, the EPO Guidelines also provide detailed instructions on the assessment of inventive step, mainly through the problem-solution approach. A concise comparison of these two approaches is presented below:


“Three-step approach” - CNIPA

Problem-solution approach” - EPO

1) identifying the closest prior art

1) determining the closest prior art

2) determining the distinguishing features of the invention and the technical problem actually solved by the invention

2) identifying the distinguishing feature(s) of the claimed invention and therefrom deriving and establishing the "objective technical problem" to be solved

3) determine whether the claimed invention is obvious to the person skilled in the art

3) considering whether or not the claimed invention, starting from the closest prior art and the objective technical problem, would have been obvious to the skilled person


Both the CNIPA and the EPO require the identification of the closest prior art as the starting point for assessing inventive step. The next step is to determine the distinguishing features of the claimed invention in comparison to the closest prior art. The CNIPA and the EPO both require examiners to identify the distinguishing features of the invention by comparing the claimed technical features of the invention with the closest prior art.


In practice, the first two steps of the two approaches are very similar. The main difference lies in the third step. For the CNIPA, at the third step, the objective is to determine whether the prior art as a whole provides any technical inspiration. Specifically, whether the prior art offers insight to apply the distinguishing feature to the closest prior art in order to address the existing technical problem (i.e., the technical problem actually resolved by the invention), which would encourage the person skilled in the art to improve upon the closest prior art when confronted with the said technical problem and ultimately arrive at the claimed invention. If such technical inspiration exists in the prior art, then the invention is considered obvious. Generally, the following are considered as having technical suggestion:


(i) the distinguishing feature is common general knowledge, e.g., the means customary in the related field for solving the redefined technical problem, or the technical means for solving the redefined technical problem as disclosed in a textbook or toolkit, etc.


(ii) the said distinguishing feature is a technical means related to the closest prior art, e.g. a technical means disclosed in other parts of the same prior art document, which plays the same role in that other part as the distinguishing feature plays in the claimed invention to solve the redefined technical problem.


(iii) the said distinguishing feature is a relevant technical means disclosed in another prior art document which plays the same role in that document as the distinguishing feature plays in the claimed invention to solve the redefined technical problem.


In the third step, the EPO adopts a “could-would approach”, whereby the question to be answered is whether there is any teaching in the prior art as a whole that would (not simply could, but would) have prompted the skilled person, faced with the objective technical problem, to modify or adapt the closest prior art while taking account of that teaching, thereby arriving at something falling within the terms of the claims, and thus achieving what the invention achieves.


These differences in the third step lead to diverse strategies and approaches when addressing examiners' objections in practice. Particularly, examiners of the CNIPA often reject the inventive step based on “common general knowledge” (公知常识), or by asserting that a distinguishing feature “is readily conceivable by the skilled person in the field” (本领域技术人员容易想到的). Unlike established practice in the EPO, in which the person making the assertion must provide proof that the subject-matter in question is in fact common general knowledge, the burden of proof of common general knowledge in the CNIPA is not explicitly outlined in the part of the Guidelines relating to inventive step. It is only stated in Part IV, Chapter 8 of the Guidelines relating to re-examination and invalidation that "the party who claims that a technical means is common knowledge in the field shall bear the burden of proof”.


In our past experience, such assertion often put the applicant in a disadvantageous position when arguing the inventive step – primarily because establishing that something is not common general is more challenging than proving that the same thing is common general knowledge.


Thus, our recommendations to European applicants are:


i) avoid relying solely on familiar argumentation ways from daily work (such as the problem-solution approach) and adhere strictly to the CNIPA's three-step approach;


ii) if you do not understand Chinese, obtain an accurate translation of the office action, at least the sections concerning inventive step. While nowadays many applicants choose machine translations of office actions for economic reasons, which is understandable and often efficient, it is sometimes crucial to scrutinize the examiner's specific wording to identify any logical loophole, or some trivial details;


iii) identifying a fulcrum to argue that the distinguishing feature is not easily conceivable by the skilled person. For example, by demonstrating that the skilled person in the field would typically solve the objective technical problem with a different approach.


Regarding point ii), the author once encountered a case where the CNIPA examiner repeatedly objects inventive step of an application, asserting that the closest prior art also disclosed one essential feature of the invention. After thoroughly reviewing the office actions, it was discovered that the examiner interpreted one feature in claim 1 as plural, while the original international application presented this feature as singular. When entering the Chinese national phase, the article for the feature was not explicitly translated, since it is common to refer to items without using articles in Chinese. Therefore, the examiner was able to interpret this feature as plural. After inserting an article “a” for the feature in claim 1, the application was granted.


Returning to the EPO’s could-would approach, the point of which is not whether the skilled person could have arrived at the invention by adapting or modifying the closest prior art, but whether the skilled person would have done so because the prior art provided motivation to do so in the expectation of some improvement or advantage.


In the practice, it is not seldom that examiners often juxtapose features of prior art documents to reject an application. This approach is particularly favored by patent examiners for example from CNIPA, JPO and KPO. However, within the context of “could-would approach” of the EPO, instead of immediately looking for potential delimiting features in an application, we recommend applicants or patent practitioners unfamiliar with the could-would approach to take a second look at the cited prior art documents to determine if the skilled person would genuinely combine them, or if is merely a hypothetical possibility.