Based on a few utility patent prosecution histories I've looked through (at least based on their "translated" documents in USPTO Global Dossier), it appears that Chinese examiners make little effort to search for prior art or make substantive arguments against claims. For instance, in one case the PCT prior art documents and arguments against patentability of all claims were merely regurgitated, after which an allowance was granted on all (slightly amended) claims.

It this "weak" examination of Chinese applications I've looked at representative of SIPO as a whole? If so, are Chinese patents worth much?

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    I don't think this can be answered, but anecdotally, sometimes they find stuff Europeans don't (because it's in Chinese or Japanese).
    – user18033
    Commented Apr 21, 2018 at 20:29
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    I didn't even bother to pursue protection in China b/c of the uncertainty regarding enforcement, even if a patent were granted.
    – DukeZhou
    Commented Apr 25, 2018 at 16:08

2 Answers 2


By way of preface, this is all opinion. As far as I know, there are no empirical studies on this.

I suspect that a US or EP examiner is much more likely to reject an application for lacking novelty or being obvious (compared to China, or for that matter, Japan, the UK, Australia, Canada etc). If your yardstick for rigor is the likelihood of rejection, then certainly those other jurisdictions are less rigorous.

However, I would question whether that is an appropriate definition for rigor. Certainly a US examiner combining 4 unrelated documents to justify a non-obviousness rejection or an EP examiner declaring that all the novel features of a claim are mere implementation details with no technical effect based on the common general knowledge does not necessarily seem rigorous to me. Instead, in my view, it demotes the patent application process in the US and EP to a crapshoot, where you can do no more than hope the examiner is in a good mood on the day.

That said, what you describe of Chinese examination seems generally representative of my experience. The Chinese examiner will generally adopt the IPRP (or the US or EP analysis, if they are available), and expect the applicant to address the rejections there. However, I should note that that is common among most offices (other the US and EP). And in fact, national offices adopting the analysis from the international phase is precisely one of the intentions of the PCT system. The fact that the US and EP choose to repeat the search and examination anew in most cases does not make them more rigorous necessarily (and I would cynically suggest they just want more search fees for themselves).

Are Chinese patents worth much?

It depends if you think a patent for one of the world's largest economies and the world's largest consumer market has any value. A Chinese patent would certainly be my third choice of jurisdiction (after the US and EP).

In fact, from the point of view of an applicant (and ignoring broader externalities), weak examination is great. An invalid granted patent has significantly more value than a refused application.

  • By lack of rigor, it seems that CN examiners spend less time understanding the prior art and invention, and merely "roll over" when arguments and (superficial) amendments come back in a response.
    – user132162
    Commented Apr 22, 2018 at 21:07
  • It's true that an invalid granted patent has some value due to the hassle of litigation, but I guess I was wondering if there is a such a perceived lack of quality in granted CN patents, that potential buyers are hesitant to buy without due diligence into validity, thus decreasing the value for the average sight unseen CN patent.
    – user132162
    Commented Apr 22, 2018 at 21:10

I have a slightly different conclusion drawn based on my experience.

I see that chinese examiners are tedious in searching prior art and their objections are almost always described in a detailed manner, which means they have at least checked that specific part of the cited prior art. I've seen them quite reluctant to grant an inventive step which usually forces chinese attorneys to narrow down the claims in a rediculously detailed manner (which in my view makes the claims non-enforcable). I am also under the strong impression that you have less chances to get a patent granted in China if you are a European (or US) applicant, than if you are a chinese one. Even smaller chances if you are a Japanese applicant! To be fair, though, US applicants have a harder time in EPO than Europeans and vice-versa, as well.

The examination style is certainly different from that of the EPO or the USPTO, but this is something expected. Chinese patent law is younger than the European or American one.

Regarding the quality of a granted patent, I tend to agree with Maca. A person working with patents may well understand that a certain granted patent is worthless. The problem is that he is rarely the one running the business or even worse, he is not a potential client. The decision maker or the potential client does not understand patents and he is usually scared off by granted patents. After all, we rarely can guarantee that the owner of a low-quality granted patent will NOT proceed to litigation, can we?

  • I have also heard that CN examiners can be partial to their own nationals in order to allow them to "catch up" and not get boxed out by foreign companies. However, like you say, this sort of favoritism seems to go on in US/EP as well (e.g. I saw two similar patent apps, one by US, one by EP, and they were each granted in their own jurisdiction and rejected in the other, and I don't think it's due to the differences in US/EP law).
    – user132162
    Commented Apr 24, 2018 at 1:06
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    I saw an extraordinary case with a chinese patent a few years ago. A classic chemical transformation, literally disclosed in the top organic chemistry book worldwide, was patented in China (only). It was key to preparing an intermediate for a blockbuster antidepressant drug. Sort of artificially creating an internal monopoly. Commented Apr 24, 2018 at 7:33
  • Yes, I agree as far as the narrowness of the Chinese patent claims is concerned. I always wondered why the claims of the Chinese patents are so narrow. You say that it is because the examiners force these ridiculously narrow claims. Commented Apr 25, 2018 at 6:59
  • The chinese examiners do force applicants (and attorneys) to rediculously narrow down their claims, but of course, as you can imagine, it is the applicants themselves that choose to go for a patent on a well known subject matter and have to add many details to get to grant. The same situation in EPO, for example, would either be rejected, or the inventive step would have been acknowledged before narrowing down too much. Commented Apr 25, 2018 at 8:25

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