Kengo Sakai


Kengo Sakai’s practice focuses on general corporate matters and commercial transactions, financial transactions, intellectual property related matters (mainly advising and representing on patent right disputes and employee invention matters), regulatory compliance, consumer law, and  litigation and dispute resolution. Mr. Sakai has wide-ranging experience centered on the fields of automobiles, aviation and IT media.


Attorney at Law


Japan (2011)


Dai-ni Tokyo Bar Association

AIPPI (International Association for the Protection of Intellectual Property of Japan)     Judicial Precedent Study Group

VPP (Association of German Patent Engineers)

Japan Association of Traffic Law

Professional Experience

2014 – present

Sonderhoff & Einsel, Law and Patent Office

2018 – 2020

Statutory Auditor, BuzzFeed Japan K.K.

2016 – 2017

Secondment to a German law firm, Preu Bohlig & Partner (Munich, Germany)

2011 – 2014

Clifford Chance Law Office



University of Tokyo Law School (LL.M.)


University of Tokyo (LL.B.)


“New Employee Invention Regulation in Japan after 2016 Amendments” (Newsletter August of Preu Bohlig & Partner) February 2017


“Patent Rights and Employee Invention Regulations: Towards Adjustment of In-house Rules related to Patent Rights” (Shonan Health Innovation Park) December, 2018


“Major Recent IP-related Rulings in Japan: an Overview” (Japan/Europe Policy Seminar “Current Trends in Japan/Europe Intellectual Property and Personal Data Protection Law” EU Japan Centre for Industrial Cooperation), 2018


“License Agreements with U.S. Companies: Provisions Which Japanese Companies Should Carefully Consider – With a Focus on Provisions Regarding Infringement and Intellectual Property under Japanese and U.S. Law.” (the Japan Pharmaceutical Industry Legal Affairs Association’s Study Group on International Issues) December 2017


“Patent Infringement Litigation in Japan“ (Japanese-German Business Association, “Intellectual Property in Japan”) October 2017


“Patent Infringement Litigation in Japan” (Seminar with Preu Bohlig & Partner, “Current Development in Intellectual Property in Japan and Germany”) October 2017


Japanese, English, German