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Atsumi & Sakai

Work +81 3 5501 2111
Fax +81 3 5501 2211
London, Tokyo

Masataka Hayakawa

Work +81-(0)3-5501-1152
Atsumi & Sakai

Work Department

Finance PG, Corporate PG, Litigaion, Arbitration, Insolvecy and Business Revitalization PG, International PG, Risk Management PG, Innovation PG


Senior Partner


Public prosecutor (2000-2014), University of Washington School of Law, visiting scholar (2006-2007), Tokyo District Prosecutors Office (Special Investigation Department) (2008), Ministry of Justice, Criminal Affairs Bureau (2008-2011)


Japanese and English.


Dai-ichi Tokyo Bar Association, The Japanese Society for Artificial Intelligence, The Association of Certified Fraud Examiners (ACFE Japan), Board member of the AI Business Creation Association, Japan Patent Attorneys Association 


The University of Tokyo (LL.B, 1999)

Japan: Risk management and investigations

Risk management and investigations – Independent local firms

Within: Leading individuals

Masataka Hayakawa - Atsumi & Sakai

Within: Risk management and investigations – Independent local firms

Atsumi & Sakai acts for Japanese and multinational companies operating in Japan on crisis management matters. The business value restoration team focuses on compliance and disclosure, while the white-collar crime group has experience in criminal defence including fraud, forgery, embezzlement, cybercrime, tax evasion, foreign bribes and felony cases. Hiroyuki Nezu jointly leads the team with Masataka Hayakawa, the latter of which focuses on corporate regulatory compliance and investigations, corporate risk and white-collar defence, among others, and  has ‘experience as a prosecutor and an officer at the Ministry of Justice in Japan, which makes his work valuable.’ Also recommended is of counsel Kohei Murakawa, who has ‘distinguished skills in global disputes’ and experience in domestic and international cartel investigations including internal audits and leniency applications.

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Japan: TMT

TMT – Independent local firms

Within: TMT – Independent local firms

The ‘prompt and responsive’ Atsumi & Sakai fields experienced domestic and international lawyers, and includes an innovation practice group which focuses on the key emergent areas of fintech, Internet of Things (IoT) and artificial intelligence (AI). Yuri Suzuki, who heads the fintech team, is assisting Mitsubishi UFJ Financial Group with the business plans, prototypes, alliances and roll out process for the company’s Digital Accelerator Program, while the IoT and AI team is jointly led by Masataka Hayakawa, Hiroyuki Sanbe and Takafumi Ochiai. The ‘approachable, supportive and knowledgeable’ Chie Kasahara leads the TMT department, which also handles the registration, protection, use and licensing of patents, model utility rights, design rights, copyrights and trade marks.

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IHL Briefings

If your firm wishes to publish IHL Briefings or articles, please contact Antony Dine on +44 (0) 207 396 9315 or


Japan: Bribery & Corruption (2nd edition)

This country-specific Q&A provides an overview to bribery and corruption laws and regulations that may occur in  Japan . This Q&A is part of the global guide to Bribery & Corruption. [Continue Reading]

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Legal Developments in Japan

Legal Developments and updates from the leading lawyers in each jurisdiction. To contribute, send an email request to
  • Taking control of a Japanese publicly listed company:

    Introductory notes for successfully completing an M&A
  • Yuasa and Hara Business Law News

    Contents of the Issue Law on liability for breach of contract Review on the amendment to the cabinet office order on Corporate Disclosure

    The Minister for Justice, Alan Shatter (“the Minister”), has published the Criminal Justice Bill 2011 (“the Bill”). The main purpose of the Bill is stated to be “…to amend the criminal law to improve certain procedural matters and strengthen Garda investigative powers. The intention is that such improvements will assist in reducing the delays associated with the investigation and prosecution of complex crime, in particular white collar crime.”
  • Japan: New legislative framework for Sukuk

    The new framework passed in May 2011 will provide a solid legal platform for issuing Sukuk Ijarah under Japanese law. NAOKI ISHIKAWA highlights key legal structures and tax treatment in respect of the anticipated Sukuk issuances in Japan.
  • Yakult Bottle Acquired Distinctiveness

    Do you know about Yakult's delicious lactic acid drink which is contained in a small bottle? Yakult's lactic acid drink (hereafter referred to as "Yakult drink") is the most famous lactic acid drink in Japan and today is also being sold in many countries around the world. When you are enjoying Yakult drink, please keep in mind the case mentioned below.
  • Tax: Japan: International Joint Ventures

    Tax on international joint ventures. Country Q&A (Japan).
  • Japan: Recent Developments in Practice and Law

    The successful closing of two Islamic fi nance transactions which was announced in July 2010 by Nomura Holdings have paved a concrete path for Japanese corporations to consider overseas Islamic fi nance markets for their fund raising activities. The fi rst transaction was in Asia for the issuance of Sukuk Ijarah and the second was in the Middle East for the establishment of a Commodity Murabahah facility (Nomura Deals).
  • Renewable energy takes off in Japan

    Like many other countries, Japan has decided to reform its renewable energy (RE) policy, to dramatically increase the use of renewable energy. The core policy mechanism is a feed-in tariff (FIT). This chapter summarises the contemplated Japanese FIT and its practical impact on existing and future investment in this sector, providing an overview of:
  • Licensing - 2010

    Q & A on Licensing in Japan 
  • Law on the Civil Jurisdiction of Japanese Courts over Foreign Countries, etc.

    The Law has been enacted to clarify the scope of application of the civil jurisdiction of Japanese courts over foreign countries, etc., and set exceptions to civil preocedings involving foreign countries, etc., based on the United Nations Convention on the Jurisdictional Immunities of States and their property (UN Convention on Immunities) (see Article 1).