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

  • Hiroharu Saito EMAIL logo
Published/Copyright: February 6, 2025
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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.


Corresponding author: Hiroharu Saito, Associate Professor of Law and Society, The Institute of Social Science, The University of Tokyo, Tokyo, Japan, E-mail:

Acknowledgments

I would like to thank all the participants at the conference, “The Past, Present, and Future of Law & Economics in Asia” held at Cornell Law School for their helpful feedback, with special thanks to the organizer, Yun-chien Chang, and the session moderator, Dawn Chutkow.

References

Ansolabehere, S., A. Gerber, and J. Snyder. 2002. “Equal Votes, Equal Money: Court-Ordered Redistricting and Public Expenditures in the American States.” American Political Science Review 96 (4): 767–77. https://doi.org/10.1017/s0003055402000448.Search in Google Scholar

Asahi, Shimbun. 2021. Kusano Koichi Shi (Bengoshi-shussin) Anketo Kaito Zenbun (2021 shuinsen).Search in Google Scholar

Charles, V., T. Gherman, and J. C. Paliza. 2022. “The Gini Index: A Modern Measure of Inequality.” In Modern Indices for International Economic Diplomacy, edited by V. Charles, and A. Emrouznejad. Cham: Palgrave Macmillan.10.1007/978-3-030-84535-3_3Search in Google Scholar

Chen, C. C.-h. 2025. “Current Status and Development of Economic Analysis in Corporate Law and Securities Regulations in Taiwan.” Asian Journal of Law and Economics 16 (1): 113–30. https://doi.org/10.1515/ajle-2024-2005.Search in Google Scholar

Chiba, K. 2019. Kenpo Harei to Saibankan No Shisen [Constitutional Precedents and the Justices’ Perspectives]. Tokyo: Yuhikaku.Search in Google Scholar

Chien, T.-S. 2025. “Economic Analysis of Private Law in Taiwan: A Return to the Private Autonomy Principle.” Asian Journal of Law and Economics, this special issue.10.1515/ajle-2024-2004Search in Google Scholar

Finkelstein, M. O. 2009. Basic Concepts of Probability and Statistics in the Law. New York: Springer.10.1007/b105519Search in Google Scholar

Horiuchi, Y., and J. Saito. 2003. “Reapportionment and Redistribution: Consequences of Electoral Reform in Japan.” American Journal of Political Science 47 (4): 669–82. https://doi.org/10.2307/3186126.Search in Google Scholar

Huang, P. C.-C. 2025. “Empirical Law and Economics in Taiwan: A Thirty-Year Review.” Asian Journal of Law and Economics 16 (1): 45–61. https://doi.org/10.1515/ajle-2024-2006.Search in Google Scholar

Ito, M. 2016. Hanrei kaisetsu [Official commentary on Supreme Court decision on September 4, 2013]. Heisei 25 nendo Saikosaibansho Hanrei Kaisetsu Minjihen 356–396.Search in Google Scholar

Khong, D. W. K., and E. X. W. Kong. 2025. “Law and Economics Scholarship in Malaysia.” Asian Journal of Law and Economics 16 (1): 103–11.10.1515/ajle-2024-2008Search in Google Scholar

Kim, J.-Y. 2025. “The Evolution of Law and Economics in Korea.” Asian Journal of Law and Economics 16 (1): 21–34.10.1515/ajle-2024-2003Search in Google Scholar

Komamura, K. 2021. “Jiron: Taishoku ‘Kazoku No Shozo’ [Faded ‘family Portrait:’ Comment on the Same Surname Case].” The Jurist 1565: 91–6.Search in Google Scholar

Kusano, K. 2011. Kaishaho No Seigi [Justice of Corporate Law]. Tokyo: Shojihomu.Search in Google Scholar

Kusano, K. 2012. Mio No Yume [Everlasting Dream: The Springtime of One International Lawyer]. Tokyo: Shojihomu.Search in Google Scholar

Kusano, K. 2016. Surihomu No Susume [Quantitative Analysis of Law]. Tokyo: Yuhikaku.Search in Google Scholar

Kusano, K. 2018. Kabunushi No Rieki Ni Hansuru Keiei No Tekihosei to Jizokukanosei [The Justifiability and Sustainability of Corporate Management Inconsistent with the Interests of the Shareholders]. Tokyo: Yuhikaku.Search in Google Scholar

Lin, L. Y.-H., and S.-K. Liu. 2025. “The Development of Law and Economics Scholarship in Hong Kong.” Asian Journal of Law and Economics 16(1): 7–20.10.1515/ajle-2025-2002Search in Google Scholar

Mori, D. 2017. “Law and Economics in Japan: 25 Years after the Hatching Stage.” Asian Journal of Law and Society 4: 287–307. https://doi.org/10.1017/als.2017.7.Search in Google Scholar

Ninomiya, S. 2021. “Fufu Doshisei No Kenpo Tekigosei [Comment on the Same Surname Case].” Koseki Jiho 814: 2–10.Search in Google Scholar

Noyama, H. 1998. Hanrei kaisetsu [Official commentary on Supreme Court decision on July 5, 1995]. Heisei 7 nendo Saikosaibansho Hanrei Kaisetsu Minjihen 633–691.Search in Google Scholar

Ogawa, R. 2022. “Fufu Doshisei Goken Kettei Niokeru Kusano Hantai Iken Wo Yomu [Reviewing Kusano’s Dissenting Opinion in the Same Surname Case].” Kenpo Kenkyu 10: 271–88.Search in Google Scholar

Ota, S. 1991. “Law and Economics in Japan: Hatching Stage.” International Review of Law and Economics 11: 301–8. https://doi.org/10.1016/0144-8188(91)90007-z.Search in Google Scholar

Pargendler, M., and B. Salama. 2015. “Law and Economics in the Civil Law World: The Case of Brazilian Courts.” Tulane Law Review 90 (2): 439–70.10.2139/ssrn.2580490Search in Google Scholar

Ramseyer, J. M. 2011. “Law and Economics in Japan.” University of Illinois Law Review 2011 (5): 1455–73.Search in Google Scholar

Saito, H., and W. Tanaka. 2023. “Sangiin Teisu Fukinko to Kofukin Haibun [Malapportionment and Subsidy Distribution: An Empirical Analysis of Japanese Upper House Elections Based on the Opinion of Justice Koichi Kusano].” Shakai Kagaku Kenkyu 74: 63–89.Search in Google Scholar

Shimizu, T. 2025. “Expansion and Transformation of Law and Economics in Japan.” Asian Journal of Law and Economics, forthcoming (paper presented at the conference).Search in Google Scholar

Singh, R. 2025. “Do Indian Courts Use Economic Reasoning in Commercial Disputes?”. Asian Journal of Law and Economics, forthcoming (paper presented at the conference).Search in Google Scholar

Takahashi, K. 2016. “Doshi Kyosei Goken Hanketsu Ni Mirareru Saikosai No Shiko Yoshiki [The Supreme Court’s Way of Consideration in its Decision on the Constitutionality of Obliged Same Surname].” Sekai 879: 138–50.Search in Google Scholar

Vo, X. V. 2025. “Recent Developments in Economics and Law in Vietnam.” Asian Journal of Law and Economics, forthcoming (paper presented at the conference).Search in Google Scholar

Watanabe, C. 2018. Sosho to Senmonchi [Litigation and Expertise]. Tokyo: Nippon Hyoron sha.Search in Google Scholar

Wu, X., and Z. Liu. 2025. “Constraints in the Economic Analysis of Law in China.” Asian Journal of Law and Economics, this special issue.Search in Google Scholar

Zhang, W. 2025. “The Development (Or Lack Thereof) of Law and Economics in Singapore.” Asian Journal of Law and Economics 16 (1): 35–43. https://doi.org/10.1515/ajle-2024-2007.Search in Google Scholar

Published Online: 2025-02-06

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