By Royal Hu
China’s 2024–2025 revision of the Patent Examination Guidelines introduced several important changes to the patent invalidation system. Among them, one update stands out for its practical impact: the refinement of the “one case, one resolution” rule, often referred to as the administrative equivalent of the “double jeopardy” or “one-and-done” principle.
Though the textual amendment appears subtle (changing “the same” to “the same or substantially the same” evidence and reasoning), the legal implications are far from minor. This adjustment aligns China’s administrative practice more closely with judicial trends already visible in the Supreme People’s Court (SPC), and clarifies how repeated invalidity challenges should be handled to balance efficiency, fairness, and public interest.
The Purpose Behind China’s “One-and-Done” Principle
In patent invalidation proceedings, the one-and-done principle prevents parties from repeatedly challenging a patent on substantially identical grounds once an administrative decision has already addressed those issues.
While the concept originates from civil procedure rules on preventing repetitive litigation, China’s patent invalidation system differs in one major respect: any party, not only the previous challenger, may file a new invalidation request.
This is because the invalidation system serves both private interests (disputes between companies) and public interests (removing wrongly granted patents). Therefore, China applies a more flexible but still structured version of the rule: as long as the evidence and reasoning are essentially the same, a new petition may be barred even if filed by a different party.
Why the New Guidelines Matter
The amendment (replacing “same” with “same or substantially the same”) serves two key goals.
1. Preventing strategic repetition disguised through small formal changes
Companies sometimes make minor adjustments to previously used documents or terminology to refile an invalidation request. The updated rule clarifies that formal modifications do not make a new case, if the substance remains unchanged.
2. Closing loopholes used to manipulate the system
In some situations, patent owners themselves strategically file “strawman” invalidation requests to consume strong prior art and “stabilize” the patent. The new rule seeks to reduce such practices, although its ultimate effectiveness will depend on how CNIPA applies it.
Judicial Precedent Already Reflects the “Substantial Identity” Standard
Even before the Guidelines were amended, the SPC had already applied a “substance over form” approach. A review of publicly available SPC judgments reveals that only a small number of cases squarely address the one-and-done question, but they show a consistent trend.
Case Example 1: Apple Invalidity Case (2023 SPC Judgment No. 332)
The SPC held that although the reasoning in Apple’s second invalidation request appeared differently worded, it sought to overturn factual determinations already made in an earlier decision.
Because the substance was the same, the CNIPA correctly refused to re-examine the issue.
Case Example 2: Dunnjun v. Weimeng (2020 SPC Judgment No. 282)
The court found that challenges framed around different claim features were fundamentally the same, because they relied on the same technical understanding.
Again, the one-and-done rule applied.
These cases demonstrate why the new Guidelines merely codify what China’s judiciary already recognized:minor linguistic or structural changes do not create new grounds for invalidation.
When the Rule Does Not Apply
Other SPC decisions illustrate situations where a new invalidation request is permissible:
1. When the evidence is genuinely new or more complete
If a party supplements missing portions of prior art or submits previously unavailable technical material, CNIPA may conduct a new examination.
2. When factual findings differ due to newly provided content
Even if prior art is the same document, new translations, clarified diagrams, or expanded sections may change the factual foundation.
3. When a prior decision was annulled for procedural flaws
If a previous invalidation ruling was overturned due to insufficient evidence or incorrect legal reasoning, CNIPA may issue a new decision based on clarified logic or additional support.
4. When earlier conclusions come from patent evaluation reports
An evaluation report is not an invalidation decision, so parallel reasoning in a later invalidation request does not trigger the one-and-done bar.
These distinctions help ensure the system remains fair, preventing abuse while still allowing necessary challenges to weak patents.
Why the Update Matters for Rights Holders and Challengers
For Patent Owners
Strong patents may become more stable once challenged, as repeat attacks on the same grounds will be limited.
However, owners cannot rely on technicalities: superficial changes will not shield them from legitimate new invalidation attempts.
For Challengers
Refiling with marginally adjusted language is no longer effective.
New evidence must be substantive, not cosmetic.
Invalidity strategy now requires careful planning to present the strongest case at the earliest stage.
For CNIPA and the Courts
Clearer rules will reduce repetitive filings and administrative burden.
Judicial and administrative standards are now more aligned, improving consistency.
Looking Ahead: A More Efficient and Predictable System
The revised Guidelines are expected to significantly reduce repetitive invalidation disputes and streamline proceedings. With clearer limits on when a second challenge is allowed, parties will face stronger incentives to present complete evidence and arguments from the outset.
Importantly, this update strengthens China’s broader IP reform goals: enhancing procedural efficiency, improving patent quality, and aligning administrative standards with judicial reasoning.
As China continues refining its patent landscape, international and domestic companies should adjust their invalidation strategies and evidence planning to operate effectively under this updated framework.