In a significant decision for patent holders, South Korea’s Intellectual Property High Court (the IP High Court) has ruled that a foreign company’s online listings of products protected by Korean patents on a Chinese e-commerce platform can be held liable for patent infringement (Decision 2023Na10693, rendered on May 22 2025). The court found that targeting Korean consumers through localised online content constitutes a domestic act of infringement even without proven sales or a physical presence in the country.
Background
An Italian sock-machine manufacturer (the Plaintiff) owned several Korean patents related to methods and devices for sock knitting.
A Chinese company (the Defendant) produced similar machines and listed and marketed them via the Chinese e-commerce platform Alibaba, as well as on its own website (with servers located in China). The listings were accessible to consumers in Korea and offered services such as product information and customer service in Korean, prices listed in Korean won, and offers of delivery to Korea.
In 2020, the Plaintiff initiated an infringement suit in a Korean district court and argued that the Defendant’s machines infringed several of its Korean patents, both device and method claims.
The Seoul Central District Court (first instance)
The Seoul Central District Court initially ruled against the patent infringement claim.
The court held that there was insufficient proof of direct sales or transfer of the machines to Korea. Similarly, the court held that there were insufficient grounds to recognise the online postings as offers for sale specifically aimed at Korea.
The Plaintiff appealed the case to the Korean IP High Court and firmly contended that the Defendant’s online posting constituted infringement under Korean patent law in and of itself.
IP High Court (second instance)
Upon appeal, the Korean IP High Court sided with the Plaintiff.
The court first addressed the issue of scope, confirming that every essential element of the Plaintiff’s Korean patents was embodied in the Defendant’s products. As a result, the accused machines were deemed to clearly fall within the scope of the Plaintiff’s patent rights.
The IP High Court agreed with the lower instance that there was no conclusive evidence of actual sales into Korea. The central question, however, was whether the Defendant’s online listings on Alibaba and its own website constituted an act of infringement in Korea. The IP High Court concluded that such activities may qualify as an “offer for assignment” in Korea, which by itself can constitute infringement.
In reaching its conclusion on whether this was the case in this instance, the court pointed to how the Defendant presented its products online. The court highlighted several key factors:
Product pages were fully available in Korean;
Prices were both displayed and payable in Korean won;
Orders could be made from Korea to ship the products directly to Korean addresses; and
Customer support (including live chat pop-ups) was provided in Korean.
Taken together, these features went beyond mere global advertising. They demonstrated, in the court’s words, a clear intent to “directly target Korean consumers” by performing the “substantive function of inducing sales” in Korea. Therefore, the court ruled that the listings qualified as a form of offer for assignment in Korea, and thus an act of infringement.
Finally, when acknowledging infringement of method claims, the court mentioned that under Korean patent law, an act of offering to use the patented method is recognised as infringement only when the infringer is shown to be aware of the infringement. In this regard, the court noted that the Plaintiff’s technology was well known in the industry and that the Defendant’s website even featured reviews comparing its machines directly to the Plaintiff’s. Combined with the fact that the Plaintiff had already sued the company in the US over the same technology, the court concluded the Defendant knew it was infringing the method claims.
The ruling
On the above basis, the IP High Court overturned the lower court ruling and issued an injunction banning the Defendant from offering to use the patented method, and from assigning, leasing, or offering to assign or lease the accused machines in Korea. The IP High Court decision has not been appealed to the Supreme Court, and became conclusive and final on June 10 2025.
The ruling marks the first time a Korean court has declared that a foreign company can be held accountable for domestic patent infringement based solely on its online marketing. It also represents a modernised view of the principle of territoriality.
Key takeaways
The ruling clarifies several important points:
Online offers can infringe patents – the ruling confirms that online offers targeting Korean consumers may amount to patent infringement, even without proven local sales;
Digital reach counts – the ruling underscores that “acts of infringement” extends to digital marketing, localised webpages, and other e-commerce activity aimed at Korea;
Practical criteria clarified – the decision highlights key factors that courts consider when assessing “offer for assignment” in Korea, such as Korean-language pages, KRW pricing, local delivery, and customer support in Korean; and
Foreign sellers on notice – manufacturers using e-commerce platforms such as Alibaba or other multilingual websites must factor in Korean IP law if their listings target Korean consumers.
