Legal 500: Corporate Governance Comparative Guide 2025
New York partners Katsuyuki Yamaguchi and Kaoru Tatsumi co-authored the Japan chapter of Legal 500: Corporate Governance Comparative Guide 2025, published by Legalease Ltd.
Authors

Mr. Tatsumi mainly advises clients on international and domestic corporate transactions such as mergers, MBOs/LBOs, joint ventures, venture capital investments and other types of M&A transactions, as well as general corporate matters and commercial disputes relating to such corporate transactions; advising major business companies, financial institutions, and private equity funds, both in Japan and overseas.
Mr. Tatsumi is one of only a few lawyers in Japan who has been seconded as an attorney to the Ministry of Justice, and during his tenure there he had a significant role in important governmental activities, such as the amendment of the Companies Act.
Drawing on his significant expertise and deep knowledge, he has authored numerous books and articles in the area of M&A, as well as general corporate law. These publications provide practical solutions to complex legal issues, and bolster Mr. Tatsumi's reputation as a highly respected legal practitioner.
North America
Competition Law / International Trade
- U.S. Importers Seek Refunds of IEEPA Tariffs at the Court of International Trade
Related Knowledge
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Vietnam Compliance Newsletter (Practical Series)
Corporate Crisis Management
Asia
- Taro HIROSAWA
- Satoshi INAMI
- NGUYEN Tuan Anh and others
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N&A Legal Forum
Inside the incident: A global crisis management tabletop workshop
Tokyo
Nishimura & Asahi Seminars
- Kaku HIRAO
- Jun KATSUBE
- Ken SAKURABAYASHI and others
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IBA Anti-Corruption Committee Asia Conference
Tokyo
External Seminars
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How Companies Should Approach LGBTQ Issues Amid Backlash
Articles
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2026年に注目すべき英国の法改正
Europe
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The International Expansion of Illegal Sports Betting and Match Manipulation, and a Public–Private Partnership Model — Japan’s Future Direction in Light of the Macolin Convention
Articles


Katsuyuki has been the Managing Partner of our New York office since its inception through 2024, and currently serves as the Chair of our New York office. He has over 30 years of experience as an M&A and corporate lawyer, and his clients include numerous listed and private companies, both in Japan and internationally. He utilizes his expertise and in-depth knowledge of both Japanese and U.S. laws to provide practical advice and solutions to clients. Katsuyuki has significant experience in Cross-border M&A, Reorganization, Joint Ventures, and Public/Startups, for both mega and middle market transactions. As a corporate lawyer, he provides advice on Shareholders' Meetings & Investor Relations, Corporate Governance, Disputes, Corporate Crisis Management, IP, Information Law, Life Sciences, and Business Succession, primarily in relation to the service, manufacturing, healthcare, telecom, and entertainment industries. Katsuyuki maintains connections with lawyers around the world, which enhances his ability to provide one-stop legal advice to Japanese companies that are doing business globally, including those expanding into the United States, Europe, China, Southeast Asia, Latin America, and Africa. Katsuyuki sits on the board of several Japanese listed companies, which provides him with the unique advantage of being familiar with both legal requirements and the needs of management, making his advice practical, insightful, and meaningful.