By Linna Song
One of the toughest challenges in patent litigation is gathering evidence of infringement. Proving that a competitor’s product falls within the scope of a patent usually requires physical inspection, technical comparison, and sometimes court-supervised appraisal. But what happens if the patent holder cannot even obtain the accused product for testing?
A recent decision of the Supreme People’s Court of China (SPC) shows that courts may still find infringement based on indirect evidence, and that defendants who refuse to disclose technical details may bear the consequences.
Case Background
In this case, a patent owner accused two companies of producing and supplying a type of high-temperature, high-pressure rotary compensator that allegedly fell within its invention patent claims. However, the plaintiff never obtained a physical sample of the disputed product. Instead, it relied on photos, online product brochures, technical manuals, and even contract documents showing product specifications.
At first instance, the trial court dismissed the claims, reasoning that the lack of physical product meant the plaintiff had not satisfied its burden of proof.
On appeal, the Supreme People’s Court took a different view.
The SPC’s Reasoning
1. Initial Burden of Proof
The Court held that if a patent owner provides sufficient indirect evidence to show that the accused product is highly likely to fall within the patent scope, the initial burden of proof is discharged. Here, the accused company itself had published brochures and catalogues showing the relevant product structure, and contracts identified the same model numbers. Together, these created a “high probability” of infringement.
2. Shift of Burden to Defendant
Once the plaintiff meets this threshold, the evidentiary burden shifts. The defendant, who controls access to technical information, must provide counter-evidence (such as original drawings, technical agreements, or inspection reports) to prove the product differs materially from the patented invention.
In this case, the defendant argued that its products contained distinguishing features (e.g., material differences, structural variations), but failed to provide credible documentation. The SPC found this insufficient, and ruled that the defendant must bear the adverse consequences of “failure to produce evidence.”
3. Outcome
The SPC concluded that the disputed products did fall within the scope of the patent. The manufacturing and sales company was ordered to stop infringement and pay damages. The downstream buyer, who had purchased in good faith at market price and put the products into public use, was exempted from ceasing use but remained shielded from liability.
Why This Matters
This ruling clarifies several important principles for patent enforcement in China:
- Indirect evidence can be enough. Patent owners should not give up when physical samples are unavailable. Brochures, contracts, online materials, and public technical descriptions may collectively establish a strong case.
- Burden shifting protects patentees. Courts will not allow defendants to “hide behind” technical secrecy. Once the plaintiff shows a credible case, the defendant must rebut with real evidence, or risk losing.
- Record-keeping is critical. For companies, proper archiving of design drawings, technical specifications, and contracts can make the difference between defending successfully and losing by default.
- Balance between fairness and practicality. The SPC also showed balance: while the manufacturer was liable, the downstream user who bought in good faith was protected. This reflects China’s attempt to ensure that patent enforcement does not unduly disrupt legitimate business operations.
Broader Significance
For international businesses and IP professionals, this case illustrates how Chinese courts are refining evidentiary rules to make patent enforcement more effective. It lowers the barriers for patent holders, especially foreign ones who often face difficulties in collecting infringing samples in China.
At the same time, it sends a warning to manufacturers: without transparent technical documentation, “stonewalling” can backfire.
Key Takeaways for Rights Holders and Businesses
Patent owners: collect and preserve all forms of indirect evidence (manuals, brochures, contracts, technical descriptions) these may prove decisive.
Defendants: maintain technical archives and be prepared to submit them in litigation; failing to do so can mean presumptions against you.
Businesses: understand that evidentiary burdens in Chinese IP law are dynamic. What starts as the plaintiff’s problem can quickly become yours if you don’t cooperate.
This decision reinforces that patents are enforceable in China even under challenging evidentiary circumstances. It reflects a maturing judicial approach that seeks fairness, encourages transparency, and strengthens the overall IP protection environment.