Akihiro Hironaka has been a partner in the dispute resolution group of the firm since 2007. He has extensive experience dealing with various large-scale and complex dispute resolution matters, both cross-border and domestic.

Mr. Hironaka is particularly renowned for his successful representation of clients in multiple large-scale disputes. For example, he succeeded in defending a notable Japanese corporation in six large lawsuits amounting to JPY 48.3 billion in total damages, filed by claimants including an affiliate company of a US-headquartered investment bank and a prominent US hedge fund. He also represented Tokio Marine & Nichido Fire Insurance in contesting a tax assessment concerning complex cross-border reinsurance transactions that transferred earthquake-related risks, and succeeded in recovering JPY 6.7 billion for his client. Furthermore, while representing the Sumitomo Trust & Banking Corporation in challenging a tax assessment related to cross-border securities repurchase transactions, he succeeded in recovering JPY 8 billion for his client.

Mr. Hironaka has also represented and advised major Japanese and international corporations, and achieved results in large scale international arbitrations (including emergency arbitrator proceedings) in Japan and elsewhere, under the rules of ICC, SIAC, AAA-ICDR and JCAA, as well as in complex product liability lawsuits, mass tort claims, cross-border disputes concerning M&A transactions and termination of distribution agreements, insurance claims, and construction disputes relating to delays at foreign construction sites located in Middle Eastern, Asian and African countries, among others.

In addition, his experience extends to advising Japanese and international corporations with respect to US discovery proceedings, Japanese judicial assistance for foreign court proceedings, Japanese legal issues pertaining to foreign court and arbitration proceedings, and US civil actions, including class actions.

Mr. Hironaka is a graduate of the University of Tokyo (LL.B., 1993) and Harvard Law School (LL.M., 2003), and he is admitted to the bars of Japan and New York. He served as a Japanese district court judge from 1998 until 2000. Furthermore, he has authored books, book chapters, and articles in the areas of litigation, arbitration, cross-border dispute resolution, product liability and tax controversy, and his representative publications include Yasuhei Taniguchi et al. (eds.), Civil Procedure in Japan (contributor, Juris Publishing), International Arbitration and Corporate Strategy (Co-author, Yuhikaku), and Frontlines of International Tax Litigation (Co-author, Yuhikaku). He is an individually ranked lawyer in the category of Dispute Resolution in Chambers Global/Asia-Pacific and the Legal 500, and in the categories of Litigation / Arbitration / Product Liability Defence / Life Sciences (Product Liability) / Professional Negligence in Who's Who Legal. Who's Who Legal Japan 2015 described him as an “experienced litigator who ‘is one of the first names that come to mind for high-stake lawsuits’”, and Who's Who Legal Japan 2016 described him as an “internationally renowned and universally respected lawyer.” Who's Who Legal 2020 said that “Peers say he is ‘extremely strategic and an expert at leading a large team’, adding: ‘There is no one else on his level.’” Asian Legal Business named him as “one of the firm’s many ‘go-to’ partners to perform strongly.” He was awarded the “Dispute Resolution Lawyer of the Year” at the ALB Japan Law Awards by Asian Legal Business in 2022, was selected among the “Asia Super 50 Disputes Lawyers” by Asian Legal Business in 2021, and was awarded Asialaw Asia-Pacific Dispute Resolution Awards: Disputes Star of the Year, Japan, in 2015 and 2016. He is a Fellow of the Chartered Institute of Arbitrators.

Recent activities


asialaw Guides 2023: Nishimura & Asahi recognized in 44 practice areas and industry groups across Japan and Asia



Recommended firm: World Tax 2023



Global Arbitration Review: Know-how Litigation - Japan 2022



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

Professional experience

2022 -
Member of List of Arbitrators, Hong Kong International Arbitration Centre
2021 -
Member, Private International Law Association of Japan
2019 -
Councilor, Japanese American Society for Legal Studies
2019 -
Fellow, Chartered Institute of Arbitrators
2016 -
Member, Japan Association of the Law of Arbitration and Alternative Dispute Resolution
Lecturer, Hitotsubashi University, Graduate School of International Corporate Strategy (ICS)
2006 -
Member, Japan Association of Arbitrators
2003 - 2004
Arnold & Porter LLP, Washington, D.C.
2001 -
Member, Japan Association of the Law of Civil Procedure
1998 - 2000
Judge of Yokohama District Court

Major Cases


Shionogi & Co., Ltd. - Rescission of tax reassessments


Rescission of tax reassessment regarding an in-kind contribution of a partnership interest


Arbitration involving significant claims and its settlement concerning a joint venture between Japanese companies relating to power plant construction projects

2015 - 2018

International Arbitration Proceedings Concerning Contractual Disputes

2015 - 2021

International Arbitration Proceedings Concerning Contractual Disputes


Provisional Measures Ordered by a Japanese Court to Assist in International Arbitration at a Foreign International Arbitration Institution


Emergency Arbitrator's Proceedings at a Foreign Arbitration Institution

2012 - 2014

Tax litigation regarding securitization transactions for domestic housing loans

2012 - 2014

Product Liability Litigation for a Major Japanese Vehicle Manufacturer

2011 - 2013

A Price Determination Dispute for Appraisal Rights of Investment Equity Relating to the Merger and Acquisition

2011 - 2013

Litigation Requesting a Declaratory Judgment for Non-existence of Injunctive Relief based on Trademark Rights

2010 - 2014

An Action Seeking Damages Relating to the Issuance of Class Shares Subject to a Class-Wide Call

2009 - 2010

Tax Litigation concerning Finite Reinsurance Policies (Tokyo High Court)

2009 - 2010

An Action Seeking Revocation of a Resolution of a Shareholders' Meeting Relating to the Issuance of Class Shares Subject to a Class-Wide Call

2008 - 2013

Large Vicarious Liability Case by a notable U.S. Hedge Fund

2008 - 2012

Large Vicarious Liability Case by an Affiliate Company of a U.S. Headquartered Investment Bank

2006 - 2013

Product Liability Litigation for a Major Foreign Vehicle Manufacturer