Japan’s New Merger Guidelines (“New Merger Guidelines”), issued by the Japan Fair Trade Commission (“JFTC”) in May 2004, mark a turning point for antitrust in Japan. It is likely that Japan’s New Merger Guidelines will be seen as a model for legal transplants in the future. Despite the similarities between Japan’s New Merger Guidelines and the U.S. Horizontal Merger Guidelines (“U.S. Merger Guidelines”), Japan’s New Merger Guidelines are unlikely to be a “success” in the same way that the U.S. Merger Guidelines have been a success since their adoption by the American competition agencies. Although Japan is far from a developing nation or a transitional economy, Japan’s experience importing critical features of the U.S. Merger Guidelines canprovide useful lessons. For developing countries also undertaking major revisions to their competition laws, Japan’s experience may show that the text of a legal transplant is only one important consideration. Additionally, the context of competition law and the subtext of changes to the existing norms of economic regulation may be just as important to “importing” antitrust law into developing nations or transitional economies.