The Inventive Step in Chinese Patent Law Compared With the U.S. Non-Obviousness Standard

By Dr. Shuo Liu
December 26, 2020

“China’s unique inventive step standard can require combining of prior art references that would not be combined in the United States, depending on how the technical problem actually solved by the invention is framed, and thus can be a slightly higher bar than the U.S. non-obviousness standard.”

China-US - China is becoming an increasingly attractive patent filing destination for foreign companies, foreign counsels are often confused by the country’s inventive step requirement. Indeed, Chinese patent examiners often use abstract legal terms, such as “prominent substantive features” and “notable progress,” in their inventive step analysis. This article provides an overview of the inventive step requirement in China, in comparison with the non-obviousness standard in the United States.

The Statutory Language of Inventive Step In Chinese Patent Law

Article 22 of the Patent Law of China requires that inventions and utility models for which patent rights are to be granted shall be ones that are novel, creative and of practical use. For inventions, having creativity means that, compared with existing technologies, the invention possesses prominent substantive features and indicates notable progress. For utility models, having creativity means that that the utility model possesses substantive features and indicates progress. Thus, utility models require a lower degree of creativity than do inventions. This article focuses on the inventiveness standard for invention patents.

The Requirement for Possessing Prominent Substantive Features

The National Intellectual Property Administration (CNIPA) issued “Guidelines For Patent Examination” (“Guidelines” hereinafter), which form the basis and standards for the administration of the China Patent Office and the Patent Review Board. The Guidelines provide that possessing prominent substantive features means that the invention is not obvious to a person skilled in the art in view of the prior art. An invention is obvious if the invention can be obtained through logical analysis, reasoning or limited experimentation on the basis of prior art by a person skilled in the technical field. Three steps are followed to determine obviousness:

  • determining the closest prior art;
  • determining the distinguishing features of the invention and the technical problem actually solved by the invention; and
  • determining whether the claimed invention is obvious to a person skilled in the art.

These three steps appear to be similar to the three factual inquiries to determine obviousness in Graham v. John Deere, 383 U.S. 1, 17–18 (1966). However, in step 2, a technical problem needs to be identified, but not the level of a person of ordinary skill in the art. It’s the opposite in Graham, where the level of a person of ordinary skill needs to be determined, but not a technical problem.

Secondary factors are also considered in China, in essentially the same manner as they are in the United States. They include solving a long-felt but unsolved technical problem, overcoming a technical prejudice (similar to prior art teaching away), unexpected technical effect, and commercial success. The Guidelines even go as far as to provide that if an invention produces an unexpected technical effect, the examiner may determine that the invention involves an inventive step, without questioning whether its technical solution has prominent substantive features.

  1. Determining the Closest Prior Art

The closest prior art refers to a known technical solution that is most closely related to the claimed invention. It can be in the same technical field as the claimed invention, or in a different technical field if the problem to be solved by the invention would prompt a person skilled in the art to look into the different field. Similarly, in the United States, analogous art can be from the same field of endeavor or in a different field as long as the reference is reasonably pertinent to the problem faced by the inventor.

For Chinese utility models, the examiner would normally focus on the technical field to which the utility model belongs (unless there is clear teaching to look to other fields). Moreover, only one or two prior art references are normally cited to assess the inventive step for utility models, although there can be exceptions.

  1. Determining Distinguishing Features and Technical Problem

In the second step, the examiner shall first determine the distinguishing features of the claimed invention as compared with the closest prior art and then determine the technical problem that is actually solved by the invention based on the technical effect of the distinguishing features. The technical problem actually solved by the invention means the technical task in improving the closest prior art to achieve a better technical effect.

In practice, Chinese examiners often characterize a distinguishing feature as common knowledge or customary means in the art, without providing any explanation. The Guidelines in its 2019 edition provide that if the applicant disagrees with this characterization, the examiner should provide proof or explain the reasoning. If the examiner determines that a technical feature contributing to the solution to the technical problem is common sense, the examiner normally should provide proof. In contrast, U.S. examiners are allowed to take official notice without providing proof when the facts are capable of instant and unquestionable demonstration as being well-known. If the applicant adequately traverses the official notice, the examiner must provide documentary evidence. Thus, China’s Guidelines appear to impose a softer requirement and give more discretion to the examiners.

The technical problem actually solved by the invention shall be determined based on the closest prior art identified by the examiner. However, the Guidelines also provide that the technical problem can be redetermined as long as a technical effect can be recognized in the description.

  1. Determining Obviousness

In the third step, the key is whether there is a motivation to apply the distinguishing features to the closest prior art in solving the technical problem. Such motivation would prompt a person skilled in the art, when confronted with the technical problem, to improve the closest prior art to reach the claimed invention. If such technical motivation exists, the invention is obvious.

The term “motivation” appears to be broadly construed to include using common knowledge, or applying a known technique from the current field or other fields to the invention to achieve the same function. This standard appears to be quite similar, if not identical, to the U.S. standard post KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 399 (2007), where the U.S. Supreme Court proposed new tests such as common sense, applying known elements, methods, or techniques to achieve predictable results, and “obvious to try,” in addition to the “teaching, suggestion, or motivation” test.

A person skilled in the art in China is characterized similarly to a person of ordinary skill in the United States, but the level of the skilled person in China does not need to be determined on a case-by-case basis as in the United States. In China, the person is presumed to be aware of all the common technical knowledge and have access to all the technologies that existed before the filing date or the priority date in the technical field to which the invention pertains, and have capacity to apply all the routine experimental means before that date. Although the person is not presumed to have creativity, the person can look to other technical fields to find answers, if a technical problem to be solved impels that person to seek technical means in other technical fields.

The Requirement for Representing Notable Progress

Representing notable progress means that the claimed invention is able to produce an advantageous technical effect as compared with the prior art, for example, overcoming defects and deficiencies in existing technology, producing a better technical effect (such as improving quality, increasing yield, saving energy, preventing or reducing environmental pollution), providing a different technical solution to solve a technical problem, or representing a new trend of technical development.

The Guidelines do not provide instructions on how to examine notable progress. As a result, Chinese examiners would usually perform the three-step analysis for prominent substantive features and conclude that the invention fails to have prominent substantive features and notable progress, without separately addressing the notable progress issue. Granted, if the invention lacks prominent substantive features, it does not involve an inventive step, with or without notable progress, although it would be clearer if the notable progress issue is addressed separately.

Six Types of Inventions And Examples

The Guidelines provide six types of invention based on the nature of the distinguishing features of the invention from the closest prior art.

  1. Ground-breaking Inventions

Ground-breaking inventions are inherently inventive by offering unprecedented technical solutions. For example, compass, paper, printing technique, gunpowder, steam engine, filament lamp, radio receiver, radar, and laser fall into this category.

  1. Invention by Combination

An invention by combination refers to combining known technical solutions to form a new technical solution to solve a technical problem. To involve an inventive step, the technical features would need to functionally support each other after the combination. If a claimed invention is a mere combination of known products or processes without any functional interaction between their technical features, the invention is obvious.

As an example provided by the Guidelines, a ball-point pen combined with an electronic watch is a mere aggregation and does not involve an inventive step because after combination, the electronic watch and the pen still function separately, without any functional interaction. In the United States, if a person of ordinary skill in the art has no reason to combine a pen with a watch, the combination would likely be non-obvious, and there is no requirement that the two components must functionally support each other. However, Chinese examiners can, in hindsight, determine a technical problem the invention actually solves, and look for existing technology to solve the problem. Here, in solving the technical problem of how to tell time when writing with a pen without having to look elsewhere, a person skilled in the art would be motivated to install an electronic watch on the pen, since it is common knowledge that an electronic watch can be used to tell time which is used here in the same way as it is usually used.

  1. Invention by Selection

An invention by selection refers to an invention made by purposefully selecting a narrower range or individual from a larger range of options disclosed in the prior art. If the invention made by selection produces an unexpected technical effect, the invention involves an inventive step. Otherwise, it would be considered obvious. Similarly, in the United States, an unexpected result is usually required to overcome prima facie obviousness in an optimization patent.

  1. Invention by Transfer

An invention by transfer refers to an invention made by applying a known technology in one technical field to another technical field. To involve an inventive step, the transfer would need to produce an unexpected technical effect or overcome a new difficulty not present in the previous technical field. For example, transferring ailerons from an airplane to submarine is considered to involve an inventive step, because the technology fields are very different and applying a technology in the air to under water needs to overcome new technical difficulties.

  1. New Use of Existing Product

An invention of new use of existing product refers to an invention made by using an existing product for a new purpose. If the new use merely involves a known property of the existing product, the new use does not involve an inventive step. If the new use involves a newly discovered property of the existing product and can produce an unexpected technical effect, the new use involves an inventive step. For example, use of pentachlorophenol as an herbicide, as compared with its prior use as a bactericide, produces an unexpected technical effect, and therefore involves an inventive step.

  1. Invention by Changing Elements

Inventions by changing elements include inventions by changing relations between elements, replacing elements, and omitting elements. Typically, the change in elements would need to produce an unexpected technical effect to involve an inventive step.

Focus on the Technical

China has a unique method of examining inventive step which requires the examiner to determine a technical problem actually solved by the invention. The invention would be considered obvious if solving the technical problem using existing knowledge would lead to the claimed invention. This unique examination method can be somewhat subjective, since the technical problem actually solved by the invention can be framed in different ways. Moreover, this method can sometimes combine prior art references that would not be combined in the United States. Thus, the inventive step in China appears to be a slightly higher bar than the U.S. non-obviousness standard. Applicants in China should focus on technical features that cannot be reasonably expected based on existing knowledge, and perhaps sometimes choose utility models over inventions.

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The Author

Dr. Shuo Liu

Dr. Shuo Liu is an associate patent attorney at Fish IP Law LLP, currently on leave to pursue an LLM degree at Golden Gate University. At Fish IP Law, he worked on patent prosecution matters and managed global patent portfolios. He received his PhD in Biomedical Sciences from the University of California, Irvine, and JD with cum laude distinction from Santa Clara University School of Law. During law school, he served as a judicial extern to the Honorable Susan Illston and the Honorable Paul Grewal at the U.S. District Court for the Northern District of California. Prior to joining Fish IP Law, he worked on patent due diligence and portfolio analysis at Jazz Pharmaceuticals.

Warning & Disclaimer: The pages, articles and comments on do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinion and views of the author as of the time of publication and should not be attributed to the author’s employer, clients or the sponsors of Read more.

Discuss this

There are currently 12 Comments comments.

  1. MaxDrei December 27, 2020 6:24 am

    In what respects does China’s jurisprudence depart from the long-established Problem/Solution Approach at the EPO. This I must ask, because you assert that it is “unique” and yet, to me, it looks like a veritable (forgive me) “Chinese copy” of the established case law of the Boards of Appeal of the EPO.

    Sir Isaac Newton advanced by standing on the shoulders of giants. Does that ever happen in China?

  2. Shuo Liu December 27, 2020 12:54 pm

    Thank you for the comments above. As the title suggests, this article compares the inventive step in Chinese patent law with the U.S. non-obviousness standard. In this context, “unique” simply means that the law in China is different from the law in the U.S. How Chinese patent law is different compared to the EPO standard would be better addressed in a different article.

  3. Andrey December 27, 2020 4:40 pm

    China’s criteria of “inventive step” is in no way “unique” – it is an approach that had been used in USSR and seems to be currently used in Russian Federation. US “non obviousness” existed in US common law (but did not exist in US legislation!) during 100 years (1852 – 1952). PRC, as well as Russian Federation, never had common law and, accordingly, any respect for precedents (“case law”). Therefore chinese patent experts simply can’t grasp the figure of “ordinary specialist in the art”, which is crucial for definition of the “inventive step”, being sure they don’t need “ordinary specialist” at all, substituting him by… logically reasoning superman, who knows everything in all fields of technology. Such approach ultimately permits not to give letters of patent to anybody.

  4. B December 27, 2020 8:15 pm

    @ MaxiDrei

    It’s not that different from U.S patent law either. Re Isaac Newton, it’s a great maxim but useless as a patentability standard. I’m still a big fan of the writings of the late Honorable Giles Rich on the issue of patentability.

  5. Benny December 28, 2020 12:44 am

    “For example, transferring ailerons from an airplane to submarine is considered to involve an inventive step, because the technology fields are very different ”
    Not so. Fluid dynamics work equally in both cases.

    The US system fails by constantly granting patents based on mere combination. Here is where the Chinese got it right.

  6. B December 28, 2020 1:09 am

    @ Benny “Not so. Fluid dynamics work equally in both cases.”

    Respectfully, the purpose of ailerons in aircraft is for turning — the functions of a rudder on a sub.

    The “ailerons” in submarines, by which I suspect you mean dive planes, have a different function, i. e., changing depth w/o blowing the ballast tanks.

  7. Benny December 28, 2020 11:06 am

    B at 6..
    Ailerons control roll, not yaw. Submarines don’t have them, but if they did, they would control the vessel’s roll.

  8. ipguy December 28, 2020 3:02 pm

    In any event, the differing standards are irrelevant if the China Examiner is like their US counterpart and applies inventive step/obviousness as they see fit instead of as intended.

  9. MaxDrei December 28, 2020 4:00 pm

    Thank you, Dr Shiu Liu. I agree. Any chance then, of an EPO vs China Patent Office obviousness comparison, any time soon?

  10. SHUO LIU December 28, 2020 4:15 pm

    @ B and Benny: I had to shorten the example due to the 2000 word limit. The Guidelines further state that the technology field is different because submarines operate differently from airplanes. A submarine remains stationary under water by balancing its weight with buoyancy, and ascends by increasing its buoyancy. In contrast, an airplane’s lift force is produced by airflow past its main wings. Also, the transfer achieved excellent technical effect, since the performance of the submarine is significantly improved.

  11. B December 28, 2020 8:22 pm

    @ Benny “Ailerons control roll, not yaw. Submarines don’t have them, but if they did, they would control the vessel’s roll.”

    Airplanes turn because of banking created by the ailerons,

    Dive planes, the closest equivalent to an aileron, do exist on subs and for another reason

    @ Shuo Liu “A submarine remains stationary under water by balancing its weight with buoyancy, and ascends by increasing its buoy”

    I spend some of my misspent youth on a Sturgeon-Class Attack Submarine – the U.S.S. Grayling (SSN-646). Sometimes you don’t want to change the ballast as it’s noisy. You can cruise at 4 knots and ascend/descend and keep fore-aft trim w/o changing the ballast with near perfect control.

  12. Felisa Bernardon January 10, 2021 1:33 pm

    That is some fantastic content! Really appreciate you sharing this for us!