Mr Keiji Tonomura > Nagashima Ohno & Tsunematsu > Tokyo, Japan > Lawyer Profile

Nagashima Ohno & Tsunematsu
TOKYO 100-7036
Keiji Tonomura photo


Mergers and Acquisitions (M&A); IP Transactions; IT and Telecommunications; Media, Game, Entertainment and Sport; Pharmaceutical and Health Care; Data Protection and Privacy; Corporate Governance; and General Corporate.


Joined Nagashima & Ohno in 2007. Became a Partner of Nagashima Ohno & Tsunematsu in 2018. Worked as a visiting attorney at Kirkland & Ellis, Chicago (2013-14).


Japanese, English.


Daiichi Tokyo Bar Association (2007; 2014).


Kyoto University (LL.B., 2004); Kyoto University Law School (J.D., 2006); Columbia Law School (LL.M., Harlan Fiske Stone Scholar, 2013).

Lawyer Rankings

Japan > Fintech - Independent local firms

(Leading individuals: Bengoshi)

Keiji TonomuraNagashima Ohno & Tsunematsu

Noted for its ‘cross-departmental collaborations’, Nagashima Ohno & Tsunematsu leverages its longstanding expertise in the field of finance to assist major Japanese banks and financial institutions with fintech work; mobile payments, robotics process automation and blockchain technology stand out as areas of activity for the firm. The team is additionally well placed to advise on business collaborations, joint ventures and acquisitions in the fintech arena. The team is led by Taku Umezawa and Keiji Tonomura, with the former possessing deep experience of financial regulations and the latter described as being ‘at the forefront of creating new DAO laws in Japan’.

Japan > TMT: Independent local firms

(Leading individuals: Bengoshi)

Keiji TonomuraNagashima Ohno & Tsunematsu

Hailed by clients as a ‘beacon of legal excellence‘, the team at Nagashima Ohno & Tsunematsu maintains its stellar reputation for advising clients on M&A and corporate transactions within the tech industry, and is particularly skilled at handling space-related matters involving cross-border business collaborations, satellite services, space tourism, and space resource mining. The team is co-led by Soichiro Fujiwara and Keiji Tonomura, whose collective experience spans the full range of TMT related issues, having both advised international and domestic clients on matters concerning software, online gaming, metaverse, robotics, and healthtech. Ryo Okubois well known for his deep experience of the telecommunication, IT, and space industries.

Japan > Intellectual property: Independent local firms

Nagashima Ohno & Tsunematsu offers a broad spectrum of expertise in IP litigation and transactional matters such as due diligence, R&D agreements, AI and big data across a range of industries. The practice is strengthened by the considerable expertise of Shunji Matsuda, as well as Kenji Tosaki, who handles IP infringement litigations and IP invalidation litigations before the IP High Court, the Supreme Court, District Courts and Japan Patent Office. They are joined by Keiji Tonomura, who specialises in cross-border IP transactions with a particular focus on the TMT industry and emergent technologies. Another associate of note is Masashi Chusho.