A recent case in China concerning the Patent Office’s burden to prove common knowledge in patent examination


To determine whether an invention involves an inventive step, the Chinese Patent Office’s Guidelines for Patent Examination (the “Guidelines”) require the patent examiner, inter alia, to make a judgment, starting from the closest prior art and the technical problem actually solved by the invention, as to whether or not the claimed technical solution is obvious to a person skilled in the art in the light of relevant reference documents and common knowledge. As the Guidelines do not give a strict definition of “common knowledge” and, in practice, the examiner is not required to prove common knowledge when he/she first introduces it, what should be qualified as common knowledge in a particular case often becomes a subject of dispute.

Recently, the Beijing IP Court handed down a decision (No. 3495 [2015]) resolving such a dispute. In its decision, the Court reaffirmed the Patent Reexamination Board (PRB)’s burden to state reasons or provide corresponding evidence for proof, if the interested party has objections to the common knowledge introduced by it. The Court further clarified the relationship between the 3GPP (a telecommunications industry collaboration that organizes several important standards from GSM through UMTS and LTE to 5G) standards documents and common knowledge, considering the increasing frequency of these documents being cited as prior art in telecommunications area.


Huawei, the plaintiff in this case, had filed a patent application “A method, system and related device for selecting a Color Ring-Back Tone (CBRT)” at the Chinese Patent Office, which was first rejected for lacking of an inventive step. Upon Huawei’s request for reexamination, the PRB of the Chinese Patent Office, the defendant in this case, upheld the rejection. Huawei then appealed this decision to the Court.

Facts of the dispute

The PRB identified a Huawei’s prior patent as the closest prior art and determined that: the distinguishing features of the current invention are that the calling party’s call request includes its CBRT ordering information and through this CBRT ordering information the calling party can request and consequently receive, among others, also the called party’s information; the technical problem solved by the invention is to enable the calling party to select a CBRT in the course of initiating a call request and receive the called party’s information, thus to improve the user experience. Huawei had no objection to this analysis.

Disputed was whether the said distinguishing features were customary technical means in the art to solve the said technical problem, thus qualified as common knowledge. If so, there would exist a technical motivation in the prior art and the invention would be obvious and lack of an inventive step. In the appealed decision, the PRB asserted so but didn’t provide corresponding evidence for proof nor state sufficient reasons, after Huawei had raised objections.

In the hearing before the Court, Huawei asserted that as the said distinguishing features were not included in the 3GPP standards documents, they should not be qualified as customary means in the art. The PRB insisted its opinion in the appealed decision and submitted additionally two patent documents as supplementary proof that a part of the said distinguishing features had already been widely used by the persons skilled in the art.

Decision of the Court

In its decision, the Court referred to the Guidelines and a prior decision (No. 2029 [2013]) issued by the Beijing Higher People’s Court, and reaffirmed the PRB’s burden to state reasons or provide corresponding evidence for proof, if the patent applicant has objections to the common knowledge introduced by it.

According to the Court, the burden should not be lowered with respect to the telecommunications area, where technologies are updated rapidly, and many emerging technologies are widely used in the industry but may not yet be included in textbook, technical manuals or technical dictionaries – the three types of proof of common knowledge enumerated in the Guidelines; even if it’s difficult to provide these proof, the PRB should state sufficient reasons, taking into account the technological development level of the telecommunications area at the given time and the degree, to which persons skilled in the art had accepted and applied the technical features in question. The Court found the two patent documents submitted by the PRB not sufficient to show that the distinguishing features in question were customary means in the art.

The Court further clarified that being included in the 3GPP standards documents cannot alone prove that a technical solution belongs to common knowledge. Besides, not every piece of common knowledge in the telecommunications area is included in the 3GPP standards documents, therefore the Court did not support Huawei’s assertion in the hearing that as the said distinguishing features were not included in the 3GPP standards documents, they should not be qualified as customary means in the art.

The Court finally reversed and remanded the appealed decision.

The full decision (in Chinese) can be accessed here:


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