The non-obviousness of an invention is assessed from the perspective of a hypothetical person known as “a person having ordinary skill in the art” (PHOSITA). Based on Paragraph 2 of Article 22 of the Patent Act, an invention is not inventive if it could have been easily accomplished by PHOSITA on the basis of prior art.^[[1]] In addition, the Patent Examination Guidelines set forth a structured methodology for assessing the inventive step of a claimed invention, which includes the following steps: (1) determining the scope of the claimed invention; (2) identifying the disclosures of the relevant prior art; (3) determining the technical level of PHOSITA; (4) identifying the differences between the claimed invention and the prior art; and (5) determining whether PHOSITA could have easily accomplished the claimed invention in view of the disclosures of the prior art and the common knowledge at the time of filing.^[[2]] Evidently, the technical level attributed to PHOSITA plays a pivotal role in the assessment of inventive step. In light of this, it is worthwhile to examine how courts ascertain the level of PHOSITA in practice. This article explores relevant judicial practice through a review of several court judgments.
 
Prior to around 2016, when assessing non-obviousness of an invention, courts tended to define the level of PHOSITA by reference to educational background and practical experience. For example, PHOSITA might be characterized as an individual “with a college or university education in optoelectronics, electronics, or electrical engineering,”^[[3]] or as a person “graduated from a college or university with a major in mechanical engineering and having at least two years of practical experience in the manufacturing, design, or repair of faucet structures.”^[[4]] However, this approach is difficult to objectively and reasonably establish the background of a skilled person. Moreover, even when the level of PHOSITA is defined in such terms, the resulting characterization remains vague and offers limited assistance in the assessment of non-obviousness.
 
Despite the inherent difficulty in defining the level of PHOSITA, its necessity and importance were expressly emphasized by the Supreme Administrative Court in its 2016 Pan Zi No. 503 Judgment. The court explained that the introduction of PHOSITA into the statutory framework is intended to prevent hindsight bias. It further held that, because establishing the level of PHOSITA is essential to an objective assessment of non-obviousness, courts should first determine the level of PHOSITA by considering factors such as the technical field to which the disputed patent pertains, the problems encountered in the prior art, the means for solving those problems, the complexity of the technology involved, and the general level of relevant practitioners.^[[5]]
 
In response to the Supreme Administrative Court’s guidance in the 2016 Pan Zi No. 503 Judgment, the Intellectual Property Court—later reorganized as the Intellectual Property and Commercial Court (hereinafter “IPCC”)—solicited and reviewed amicus briefs and conducted an in-depth discussion on the role of PHOSITA in the assessment of non-obviousness in its 2016 Xing Zhuan Geng (1) Zi No. 4 Judgment. The IPCC reached, inter alia, the following conclusions:^[[6]]

1. The technical level of PHOSITA may be substantively reflected by the prior art itself.
2. Accordingly, it is not always necessary to expressly define the knowledge or technical level of PHOSITA as of the filing date of an invention.
3. Nevertheless, where the parties dispute a particular level of PHOSITA that would affect whether certain knowledge or techniques may be relied upon as evidence, it may still be necessary to define the level of PHOSITA explicitly.
4. The party asserting that an invention lacks an inventive step bears the burden of explaining why PHOSITA could have easily accomplished the invention based on the prior art.

 
Another noteworthy decision is the Supreme Administrative Court’s 2017 Pan Zi No. 651 Judgment, which has frequently been cited by the IPCC in cases involving disputes over the level of PHOSITA. In that judgment, the Supreme Administrative Court held that the technical level of PHOSITA should be objectively ascertained on the basis of the evidence presented in each specific case. The court further reasoned that, where the parties have debated the differences between the disputed patent and the cited prior art, as well as whether the invention could have been easily accomplished in light of the prior art and the common knowledge at the time of filing, such debate also encompasses the issues of PHOSITA and his or her technical level at the time of filing. Consequently, if an appellant merely asserts that the original judgment failed to explain or discuss PHOSITA, without submitting evidence regarding the level of PHOSITA and demonstrating how a different assessment of that level would have altered the conclusion on inventive step, the appellant cannot be regarded as having adequately shown that the original judgment was legally flawed.^[[7]]
 
Similarly, in its 2017 Cai Zi No. 597 Ruling, the Supreme Administrative Court held that PHOSITA is a hypothetical construct whose technical and creative capabilities must be concretized through extrinsic evidence and may gradually emerge during the parties’ arguments on non-obviousness. The court further noted that, so long as the court’s reasoning does not violate rules of experience, principles of logic,  or laws of nature, it is difficult to conclude that the court failed to explain the knowledge level of PHOSITA.^[[8]]
 
In summary, certain judicial decisions have taken the view that the level of PHOSITA can be sufficiently reflected by the prior art per se, such that the absence of an explicit determination of PHOSITA’s level does not necessarily constitute a legal error. Nevertheless, in its more recent 2024 Tai Shang Zi No. 453 Judgment, the Supreme Court has again underscored the necessity of the step of establishing PHOSITA’s level when assessing the non-obviousness of an invention.^[[9]] This indicates that the issue remains unsettled in judicial practice. The IPCC has recently rendered several judgments that include a dedicated section stating that the level of PHOSITA is ascertained on the basis of the technical field of the disputed patent and the evidence on record.^[[10]] Whether this approach adequately satisfies the requirement to establish the level of PHOSITA in the assessment of non-obviousness remains a question that warrants further observation.