Uniqlo, part of Fast Retailing, sued Shein in Japan, accusing the Chinese retailer of copying its popular Round Mini Shoulder Bag.

The entities that operate the Shein brand must immediately cease sales of "imitation products” and compensate for damages, Fast Retailing said in a statement Tuesday.

The bag, sold for around ¥1,500 in Japan, has become a global hit, with Uniqlo warning consumers about counterfeits and similar products being sold online. Fast Retailing joins rival Hennes & Mauritz in suing Shein for copyright infringement in Hong Kong, where litigation aimed at mitigating the threat posed by the Chinese rival has been underway since 2021.

Representatives for Shein, which was founded in China and is now based in Singapore, didn’t immediately respond to requests seeking comment. Uniqlo filed the lawsuit against Roadget Business, Fashion Choice and Shein Japan on Dec. 28 at the Tokyo District Court.

"The company filed this complaint because it has determined that the form of the imitation products sold by Shein closely resembles that of its own product,” Fast Retailing said in the statement. "The sale of the imitation products by Shein significantly undermines the high level of customer confidence in the quality of the Uniqlo brand and its products.”