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.

Recent activities


The Legal 500: Corporate Governance Comparative Guide



The International Comparative Legal Guide to Corporate Governance 2019: Japan



The Legal 500: Corporate Governance Comparative Guide



Duke University School of Law (LL.M.)
The University of Tokyo (LL.B.)

Professional experience

2018 -
Nishimura & Asahi NY LLP
Member, The Companies Act Advisory Group for the JICA Legal and Judicial Development Assistance Project in Myanmar
Examiner, The Japanese Bar Examination (Commercial Law)
2013 - 2015
The Ministry of Justice, the Civil Affairs Bureau (specializing in the Companies Act)
2012 - 2013
Kirkland & Ellis LLP, Chicago