Man Energy Solutions (MES), a Danish company, filed a petition with the Intellectual Property Trial and Appeal Board to invalidate the dual-fuel marine engine patent held by the Swiss company WinGD, but the IPTAB decided that the patent was valid. AIP, representing MES, pursued legal actions in the Patent Court, resulting in the reversal of IBTAP’s decision, and effectively invalidated WinGD’s patent. AIP also secured a favorable ruling in the Supreme Court, where WinGd’s appeal was dismissed, and the patent was ultimately decided as invalid in the final decision. This is a noteworthy case of an international patent dispute between two European companies in Korea.