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Home > Lawyers > Partners > Masato Tanaka

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Masato Tanaka


Masato Tanaka is a partner at Nagashima Ohno & Tsunematsu. Mr. Tanaka advises clients regarding a wide variety of intellectual property matters, including patent, copyright, branding strategy, and countermeasures against unfair competition and counterfeit goods. Primarily, based on his IP expertise, he focuses on patent litigation and counseling. His patent litigation experience includes handling matters before district courts, the IP High Court, the Supreme Court, and the Japan Patent Office (JPO). He also provides pre-litigation patent counseling, including infringement/invalidity analysis.

Mr. Tanaka served on the Committee for Patent Systems at the JPO and served as an ad hoc member of the Industrial Structure Council, of the Ministry of Economy, Trade and Industry. He currently serves as an Appeal Examination Counselor at the JPO. He is also a member of the Intellectual Property Committee of the Japan Federation of Bar Associations.

Prior to joining Nagashima Ohno & Tsunematsu, Mr. Tanaka served as an IP High Court Judge, where he extensively handled patent litigation.

Education/Professional Experience


Waseda University (LL.B.)


Assistant Judge


Judge (Osaka District Court, Judicial Research Official of the Supreme Court, Director of Recruitment Division, Personnel Affairs Bureau, General Secretariat, Supreme Court, the Tokyo High Court, the Intellectual Property High Court)


Partner, Nagashima Ohno & Tsunematsu


Appeal Examination Counselor of the Japan Patent Office

2010-2015, 2016-2021

Professor of Law, Waseda Law School (2007-2010 Visiting Professor)


September 11, 2018

NO&T Seminars

ADVANCE Corporate Law Seminar - Pioneering the Frontier in Corporate Law
2018 Part 5 Domestic Litigation Seminar "Latest Corporate Litigation Practices"

April 26, 2016

NO&T Seminars

ADVANCE Corporate Law Seminar - Pioneering the Frontier in Corporate Law
2016 Part 2 IP Seminar
"Latest Intellectual Property Issues (NO&T IP Forum 2016)"


October, 2006


Patent Invalidity Defence in Patent Infringement Litigation in Japan

The Asialaw Japan Review, Volume 2 Issue 2, October 2006