This article compares trade secret protection in the United States and Japan in light of the different economies and cultures of the two nations. Part I provides a background for comparison by describing the theory and purposes of trade secret protection in the United States and examining the legal, business, sociopolitical, and economic significance of that protection. Part II describes the crucial distinction in American law between the tort law of trade secrets and contractual protection of confidential information. It then outlines the role of criminal sanctions in protecting private trade secrets and the civil remedies available in the United States for their misappropriation, focusing on the role of the injunction in providing effective relief. Part III analyzes the status of trade secret protection in Japan by reviewing key decisions of the Japanese courts and the observations of leading Japanese commentators, and it notes the practical effect of the remedies (and the lack thereof) in those decisions. Although Japanese case law is sparse, there are now enough decided cases and scholarly commentaries to suggest that Japanese law lacks a vital feature of American trade secret law: effective relief for third-party misappropriation. Finally, Part IV analyzes the cultural and political reasons for the weakness of trade secret protection in Japan, discusses the forces for change, and provides a prognosis for the future.