Law and Economics in Japan’s Courts: Emerging Trends and Developments

Abstract This article briefly reviews the emerging trends of incorporating law and economics perspectives within the Japanese judiciary. In the first part, I review opinions of Justice Koichi Kusano, the first justice in the history of the Supreme Court to adopt law and economics approaches. In particular, I discuss his two key approaches: the maximization of well-being and the use of quantitative empirical analysis. In the second part, I explore the broader judiciary context, including transformations in the Supreme Court’s majority opinions and the practices of lower courts and lawyers. Specifically, I highlight the Supreme Court’s growing emphasis on empirical data, particularly concerning social circumstances and public attitudes. Additionally, I analyze the subsequent shift in lawyers’ practices, which increasingly include the submission of survey data and statistical evidence. I also present emerging trends in the annual number of court decisions that reference regression analysis.