Many claim that although formal trade barriers have been removed at the border, Japanese markets remain unusually closed because of non-tariff barriers. After describing Japan's development strategy and the debate over the sources of Japanese growth, we consider current trade barriers. Recent research has made some headway investigating the impact of one of the alleged "invisible" barriers. In particular, efforts have been made to test if the behavior of Japanese corporate groups, known as keiretsu, creates a barrier to trade. Finally we consider whether private sector trade restrictions warrant a public response; what, if anything, should be done about keiretsu?