Similar Ultimate Question, Different Analytical Architecture
Both China and the United States reject claims that do not rise sufficiently above the prior art. That surface similarity can tempt cross-border teams to reuse the same argument structure. The danger is that each system directs attention differently.
CNIPA practice is strongly associated with the three-step approach in the Guidelines for Patent Examination: identify the closest prior art; determine the distinguishing features and the technical problem actually solved; then decide whether the prior art as a whole provides a technical teaching that would have motivated the skilled person to reach the claimed solution.
U.S. obviousness under 35 U.S.C. §103 is framed through the factual inquiries of Graham v. John Deere and the flexible approach of KSR v. Teleflex. The analysis considers the scope and content of the prior art, differences between the prior art and the claims, the level of ordinary skill, and relevant objective evidence, while allowing multiple articulated rationales for combining or modifying teachings.
CNIPA: The Technical Problem Is a Structural Part of the Analysis
In the CNIPA three-step method, the formulation of the “technical problem actually solved” is not mere background wording. It links the distinguishing feature to its technical effect and frames the later inquiry into technical teaching.
CNIPA’s 2023 Guidelines revision specifically emphasized avoiding hindsight when formulating that problem. The problem should match the technical effect of the distinguishing feature, but it should not contain the distinguishing feature itself or language that points toward the claimed solution. If the problem is framed as “how to add feature X,” the answer may be built into the question.
This makes technical-effect support especially important. A claimed distinction that produces an effect clearly reflected in the specification can support a more accurate problem formulation. A distinction presented without a supported effect may be easier to characterize as a routine alternative.
The “Closest Prior Art” Starting Point Matters More Explicitly in CNIPA Practice
CNIPA’s method begins by selecting a closest prior-art reference—the technical solution most closely related to the claimed invention. The starting point shapes the identified distinguishing features, the technical problem, and the later teaching analysis. Different starting references can therefore produce different obviousness pathways.
U.S. law does not impose the same mandatory “closest prior art” sequence as a formal prerequisite. An examiner may rely on multiple references and recognized rationales, provided the rejection establishes the factual basis and explains why a person of ordinary skill would have made the proposed combination or modification with a reasonable expectation of success where required.
That difference matters when translating an argument. Telling a U.S. examiner that reference A is “not the closest prior art” is not, by itself, a complete answer to §103. Conversely, importing a broad KSR-style rationale into CNIPA practice without addressing the technical problem and technical teaching can miss the structure of the Chinese analysis.
The same prior-art facts may need to be organized differently. Cross-border prosecution is not merely translation of conclusions; it is adaptation of the reasoning path to the governing legal framework.
USPTO: Graham Provides the Facts; KSR Keeps the Reasoning Flexible
MPEP §2141 reiterates that obviousness is a legal conclusion based on underlying factual inquiries from Graham. After KSR, the USPTO is not confined to a rigid teaching-suggestion-motivation formula. MPEP §2143 lists recurring rationales, including combining known elements according to known methods, simple substitution, use of a known technique to improve similar devices, “obvious to try” reasoning in appropriate circumstances, and design incentives or market forces.
Flexibility does not mean an examiner can simply say “common sense” and stop. The rejection still needs an articulated reasoning with rational underpinning tied to the record. The applicant can attack the factual premise, the applicability of the rationale, incompatibility among teachings, lack of reasonable expectation of success, teaching away, or objective evidence where supported.
“Motivation to Combine” Is Not the Same Concept in Every Argument
CNIPA’s third step expressly asks whether the prior art as a whole provides technical teaching that would motivate the skilled person to apply the distinguishing feature to solve the identified problem. U.S. practice also requires a reason for the proposed modification or combination, but after KSR that reason can come from a broader set of sources and rationales than an express statement in the references.
That is why a U.S. response that says only “there is no teaching, suggestion, or motivation in the references” is often incomplete. The stronger response asks what rationale the examiner actually invoked and then tests that rationale against the technical and evidentiary record.
Drafting Implications: Preserve the Technical Story
The systems differ in analytical structure, but both reward a specification that explains what the claimed differences actually do. For Chinese practice, technical effect can shape the problem formulation and technical-teaching analysis. For U.S. practice, a clear technical story can support arguments about why a modification is not predictable, why references address different problems, why the proposed combination changes principle of operation, or why objective evidence has a nexus to the claimed invention.
A cross-border draft should therefore avoid presenting the invention only as a list of components. It should explain relationships, technical effects, alternatives, and why particular combinations matter. That record gives later counsel more than one way to defend inventiveness.
Why the Difference Matters for Patent AI Evaluation
Legal AI systems can make a subtle cross-jurisdictional error: they identify a familiar concept such as “motivation to combine” and assume the analytical framework is identical everywhere. A fluent answer may then apply CNIPA’s three-step terminology to a USPTO rejection or import U.S. KSR rationales into a CNIPA analysis without addressing the technical problem actually solved.
For AI evaluation, jurisdiction is therefore a first-order criterion. A good model answer should identify the governing framework, organize facts in the sequence that framework requires, and avoid treating similar vocabulary as proof of identical doctrine.
A Working Comparison
- Starting structure: CNIPA generally uses closest prior art → distinguishing features/technical problem → technical teaching; USPTO uses Graham factual inquiries under a flexible KSR framework.
- Problem formulation: explicitly central in CNIPA’s three-step method; relevant in U.S. reasoning but not a mandatory second-step formulation.
- Combination rationale: CNIPA asks for technical teaching connected to the problem; U.S. law permits multiple articulated rationales beyond express TSM.
- Hindsight: both systems seek to avoid hindsight, but the doctrinal safeguards are expressed differently.
- Drafting consequence: both benefit from a specification that documents technical relationships and effects rather than only the desired result.
Takeaway
CNIPA inventive step and USPTO obviousness are not opposites, and one is not inherently stricter than the other. They are different analytical architectures applied to a related patentability question. The practical mistake is assuming that a successful argument in one jurisdiction can be translated word-for-word into the other.
For Chinese applicants going abroad, the better approach is to preserve the technical substance once, then adapt the legal reasoning to the jurisdiction. That is also the standard a serious cross-border patent AI system should be expected to meet.