In a case decided under docket (2025) Zui Gao Fa Zhi Min Zhong No. 805, published by the Supreme People's Court (SPC) Intellectual Property Tribunal in August 2026, the SPC affirmed dismissal of an infringement claim over a dog-shoe patent because the patent owner had already disclaimed the accused design during examination. The Tribunal held that a patentee cannot use the doctrine of equivalents to pull a technical solution back into the claim after explicitly abandoning it in statements made while winning the patent. Foreign companies that enforce Chinese patents, or defend against them, should read this ruling, because the doctrine cuts both ways.

Note on the deciding body: the case was heard by the Supreme People's Court itself, on appeal, with the SPC's Intellectual Property Tribunal — the SPC's internal specialized division for patent and other technical IP appeals — handling the matter and publishing the case analysis. It is not a separately constituted "IP court"; the judgment is an SPC second-instance ruling.

Article 6 of the SPC's Interpretation on Several Issues Concerning the Application of Law in Patent Infringement Disputes (法释〔2009〕21号, effective 1 January 2010, amended in 2020 by 法释〔2020〕19号) provides that a court must not support a patentee who gave up a technical solution — through amendments to the claims or the description, or through statements made during prosecution, reexamination, or invalidation — and later tries to reclaim it in an infringement suit. Article 13 of the SPC's second interpretation (法释〔2016〕1号, also amended in 2020) adds the main recognized exception: if the patentee proves the narrowing amendment or statement was expressly rejected by the examiner, the disclaimer never took effect.

These two provisions are the generally cited statutory basis for the doctrine; the SPC's own case commentary on this dog-shoe decision does not itself cite article numbers — it states the rule in general terms and leaves the codification to the reader.

Chinese patent owners rarely think about what they told the examiner years earlier. The dog-shoe case is a reminder that those statements are permanent. They sit on the record, they bind the patentee, and they can be turned against the patent in court.

The dispute centered on an invention patent titled "Dog Shoe," owned by an individual identified in the published commentary as Yang Moubo and licensed to a company (referred to in the commentary only by a redacted name) that brought the suit. Claim 1 described a strap that, in its fastened state, pulls both sides of the shoe toward the middle; the strap sits between the position for the dog's dewclaw and the position for the dog's toe joint, such that in use the extension of the strap's pulling-force direction passes through the area of the dog's paw pad. Claim 3, dependent on claims 1 or 2, additionally required that the shoe's heel counter be substantially arc-shaped and that the extension of the strap's pulling-force direction be substantially perpendicular to that arc. The plaintiff sued a manufacturer (also referred to only by a redacted name) and sought RMB 500,000 in total, covering both damages and reasonable costs of enforcement — not RMB 500,000 in damages with costs added on top.

During examination, the patentee responded to the first office action from the China National Intellectual Property Administration (CNIPA). To distinguish the amended Claim 1 from a cited reference, the patentee stated that the strap in the amended claim differed because it did not bind the ankle/foot and did not restrain a large area of the foot's upper surface. That single sentence became the whole case.

The first-instance court found the accused product's technical solution lacked the features of Claim 1 and also fell outside Claim 3, and dismissed the suit in full. On appeal, the SPC affirmed — dismissing the appeal and upholding the original judgment — but reasoned it through prosecution history estoppel specifically as to Claim 1. The patentee's own prosecution statement, the court held, showed the patentee had already abandoned any design that covers a large area of the foot's surface or binds the ankle. The accused product used exactly that abandoned design. As a result, the accused product's features regarding strap position and the direction of pulling force were neither identical nor equivalent to the corresponding features of Claim 1 — so the accused product did not fall within Claim 1, and consequently did not fall within Claim 3 either.

The doctrine operates as a limit on the doctrine of equivalents. Chinese courts do let a patentee assert equivalents beyond the literal claim wording. They will not, however, let a patentee use equivalents to recapture ground it conceded during examination, reexamination, or invalidation.

Chinese courts have recognized the doctrine of equivalents since 2001, when the SPC's Several Provisions on the Application of Law in Patent Disputes (法释〔2001〕21号) first set out the rule, effective 1 July 2001. The estoppel limit on that doctrine was codified roughly eight years later in Article 6 of the 2009 interpretation — the provision generally cited for the rule applied in the dog-shoe case — though Chinese courts had applied a version of the doctrine in individual cases even before 2009; the interpretation codified rather than originated the practice.

Two features of the Chinese rule stand out. First, no formal claim amendment is required — a statement made in response to an office action is enough, which is what happened here. Second, whether the examiner actually relied on the statement, or whether it caused the grant, generally does not matter for finding a disclaimer; the main recognized exception is where the patentee shows the narrowing statement was expressly rejected by the examiner, in which case the disclaimer is treated as never having taken effect.

The doctrine serves a public function. It keeps the published claim reliable, so competitors can design around the patent and trust that the scope they read is the scope they face. The SPC's case commentary describes the rule as guarding against a patentee "gaining on both ends" — winning a narrow claim during examination and a broad claim in court. (This phrase comes from the SPC Tribunal's published case analysis, not from a direct quotation in the judgment itself.)

If your company holds Chinese patents, pull the prosecution file before you threaten anyone. The claims on the face of the patent are not the whole story. The file wrapper from CNIPA — office action responses, reexamination submissions, and invalidation submissions, along with office action notices and any hearing or interview records — defines the outer edge of what you can actually assert. Four practical steps follow:

First, audit your Chinese portfolio's file histories. Flag any statement where your agent or in-house counsel narrowed a claim, narrowed the description, or distinguished a reference. Those statements will resurface in litigation.

Second, before sending a cease-and-desist letter or filing suit, test the accused product against the disclaimed scope, not just the granted claims. If the accused design matches something you gave up, the case is weak from the start.

Third, write office action responses as if a court will read them in ten years. Avoid broad disclaimers like "our invention does not cover X." State the narrow distinction you actually need.

Fourth, remember estoppel is one of two related limits on equivalents in Chinese law — the other is the doctrine of dedication to the public (Article 5 of 法释〔2009〕21号), under which a technical solution described in the specification but not claimed is treated as dedicated to the public and cannot later be recaptured through equivalents either. A full file-wrapper review should check for both.

If your company is the defendant in a Chinese patent suit, obtain the patentee's full prosecution history early. The disclaimer that defeats an infringement claim is often buried in the first office action response, as it was in the dog-shoe case.

The immediate effect is on enforcement economics. A patent that looked broad may, after a careful file wrapper review, turn out to cover only a narrow commercial design. That changes licensing leverage, settlement value, and the decision to litigate at all.

There is a second effect for foreign businesses. This ruling signals the SPC will hold patentees to their prosecution record, which protects the public's reliance on the published claim. Companies that design around a Chinese patent can read the prosecution history as a reliable map of the safe zone. Companies that own Chinese patents should treat that same history as a liability to be managed.

For companies buying or licensing Chinese patents, the ruling adds a due-diligence step. A patent's apparent claim breadth can mislead if the file wrapper contains narrowing statements. Any acquisition or licensing review of a Chinese patent should now include a read of the prosecution history, not just the granted claims.

The court's reasoning also addresses the double-benefit problem: a patentee should not be able to argue narrow during examination to win the patent, then argue broad in litigation to win damages. The SPC's case commentary points to this as exactly the abuse the doctrine exists to prevent.

For any foreign company with real exposure in China, the message is short. Review the file wrapper before you litigate, on either side of the case. The cheapest defense in a Chinese patent dispute is often a sentence your opponent wrote to the examiner years before the dispute existed.