Lee & Ko represented Webzen, a leading Korean game company, in a case before the IP High Court (appeal from a decision of the Intellectual Property Trial and Appeal Board (“IPTAB”)), where the key issue was whether the trademark application for 'MU' should be refused on the grounds that it was a simple and common mark. On January 23, 2025, the IP High Court ruled in favor of Webzen, finding that the 'MU' trademark had acquired distinctiveness as an indicator of a specific source, and therefore granted full relief to Webzen. The judgment became final and conclusive on February 18, 2025.
'MU' is the mark of Webzen’s flagship online game, which has been in use for more than 23 years since the launch of the game MU in 2001. Building on the success of 'MU', Webzen subsequently released a series of related titles, including the MU Series (such as MU Origin), which have also achieved great success. In this case, Webzen applied in 2021 to register the word mark 'MU' without any stylization. However, the Korean Intellectual Property Office (“KIPO”) issued a decision refusing the application on the grounds that 'MU', as a simple combination of the capital letters “M” and “U” without stylization, constituted a simple and common mark lacking distinctiveness under Article 33(1)(vi) of the Trademark Act. Webzen’s subsequent appeal (appeal against refusal of trademark registration) before IPTAB was likewise dismissed.
Starting from the IP High Court stage, Lee & Ko newly took over the representation of Webzen and filed an appeal seeking to overturn the IPTAB’s refusal decision. In doing so, Lee & Ko presented extensive evidence of Webzen’s use of the ‘MU’ mark over the roughly 23 years between the launch of the MU game and the time of the IPTAB decision, as well as materials showing the concurrent use of MU, MU Series and
, thereby demonstrating that repeated use of the common ‘MU’ element had significantly enhanced the distinctiveness of the mark and persuading the court through a multifaceted presentation. As a result, the IP High Court held that, given Webzen’s continuous use of “MU” and related marks since 2001, the ‘MU’ mark itself had acquired distinctiveness through use by the time of the decision, thereby allowing Webzen to successfully secure registration of the trademark. This case underscores how thorough legal analysis on acquired distinctiveness, combined with the passionate collection and presentation of evidence, resulted in persuasive advocacy and the successful protection of a key trademark, fully demonstrating the expertise and accumulated know-how of Lee & Ko’s Intellectual Property Practice Group.