Chang Tsi & Partners
Firm overview:
Boutique firm Chang Tsi & Partners offers an integrated model that covers the whole IP lifecycle, fielding interdisciplinary teams with expertise across multiple jurisdictions. Rated ‘Outstanding’ in WIPR’s PRC Trademarks Rankings for 2025, the firm is noted in the Patents Rankings this year for its non-contentious work. Chang Tsi’s patent practice has been gaining recognition, and in March 2024 it was awarded the highest ‘5A’ rating by Beijing Patent Attorneys Association.
Chang Tsi shows significant capability in non-contentious patent matters, having guided Baidu’s global artificial intelligence and driverless car patent filings, and Air China’s patent strategy. Design patents are a particular specialism, with the firm reporting a significant increase in filings in 2024.
The firm has proved itself a safe pair of hands for multi-patent, multi-jurisdictional disputes with a strong track record of success. Recent highlights include wins in patent invalidation and enforcement matters for Intercontinental Great Brands (Oreo) and Skechers.
Team overview:
Chang Tsi & Partners has 350 professionals across offices in its Beijing headquarters and Shanghai, Guangzhou and Shenzhen, as well as branches in the US, Korea, Hong Kong SAR, Taiwan, and Guangxi.
Its patent team combines technical expertise with litigation experience. More than a third of practitioners are dual-qualified as lawyers and patent attorneys, and the team also includes former senior judges and China National Intellectual Property Administration (CNIPA) examiners.
Deputy director of the firm Nancy Qu is responsible for the overall management of the patent practice, and renowned for her proficiency in design patent litigation and unfair competition disputes. Qu’s representative clients include Skechers, Guinness World Records, Graco, Carlisle, and 3M.
Michael Wu oversees the firm’s Shenzhen branch. An expert in SEP/FRAND litigation, Wu has secured landmark wins in cases relating to telecoms and software, and provides strategic advice on cross-border disputes.
Chang Tsi strengthened its patent team in February 2025 with the addition of Ryan Xu who joined from Bird & Bird. Xu, who has also served as a patent examiner and licensing manager at the CNIPA, brought extensive experience in patent litigation, invalidation and administrative proceedings to the firm.
Key matters:
- Air China: International patent filings, patent mining, patent ownership negotiation
The team acted as strategic IP counsel for Air China in a series of matters involving international patent protection, technology evaluation, and ownership negotiations.
The work included the preparation and prosecution of patent applications in the electrical and mechanical engineering fields; comprehensive patent mining; and advising on a sensitive ownership negotiation involving a co-developed project with a supplier. This matter was selected as one of the ‘Top 10 IP cases of 2024’ by the Jinan Intermediate People’s Court.
Key team members are partner Nancy Qu and attorney-at-law Wendy Wei.
- Skechers v Guangdong Camel Clothing & Others
Leveraging its design patent specialism, the team represented Skechers in a high-profile design patent infringement dispute against multiple Camel-branded entities selling allegedly infringing footwear.
Skechers alleged the defendants’ shoes fell within the scope of its protected design patent and sought urgent injunctive and compensatory relief. The first instance proceedings have been completed and jurisdictional challenges resolved in favour of Skechers.
Chang Tsi’s team included partner Nancy Qu, and counsel/patent attorneys Rose Xu, Phoebe Xi, Irene Wang and Jessie Wu.
- Baidu: Strategic patent filing and high-stakes patent litigation
Chang Tsi’s representation of Baidu, which dominates China’s search engine market with a share of approximately 56% across all platforms, indicates the team’s top level technical expertise.
On behalf of Baidu, the team handled multi-jurisdictional patent filings covering AI, autonomous driving and advanced search technologies in key markets.
Chang Tsi also acted for Baidu in four invention patent infringement lawsuits before the Beijing Intellectual Property Court, which addressed the issue of internet software patent infringement determination. Two cases were withdrawn after the Patent Reexamination Board invalidated the asserted patents, and two remain pending in the first instance.
Counsel Franklin Fu, attorney-at-law Xiaohan Wang and patent attorney Cathy Xiao are the key team members.
Clients:
Air China, Arkema, ITW, Johnson & Johnson, Kohler, Macrogenics, Master Kong, Morgan, Sennics, Skechers, Tokyo Electron
