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Hiroko is a partner in the litigation and arbitration team.
She focuses on cross-border dispute resolution matters, including Japanese and US litigations and anti-trust investigations, with a particular emphasis on international commercial arbitrations and contentious intellectual property cases.She has represented leading Japanese, US, and Asian companies in various and complex arbitration cases concerning international contract disputes under the auspices of the ICC and JCAA. Hiroko also has experience in litigation ancillary to international arbitrations, including parallel court proceedings and motions to set aside arbitral awards before the Tokyo District Court.
Her expertise in intellectual property disputes ranges from defending multinational companies against internet-related copyright infringement and defamation claims in Japanese courts to acting for Japanese and Asian clients in US patent infringement litigations. She is also a domain name dispute panelist for the Japan Intellectual Property Arbitration Center (JIPAC) and the Asian Domain Name Dispute Resolution Centre (ADNDRC).
Prior to joining Withers, Hiroko worked at Mizuho Bank for nine years engaged in human resources operations. Subsequently, she spent 16 years at O'Melveny & Myers LLP handling cross-border dispute cases.
Track record
A global network service provider
Defended a global network service provider in a Japanese litigation from internet-related copyright infringement claims brought by major Japanese content providers.
A multinational internet security company
Acted for a multinational internet security company in several internet-related copyright infringement and defamation lawsuits in Japan brought by Japanese individual right holders.
An American manufacturer in a major ICC arbitration
Acted for an American manufacturer in a major ICC arbitration against a Japanese company arising out of a licensing agreement relating to trade secrets.
Global manufacturing companies
Successfully represented global manufacturing companies in parallel court proceedings in a Japanese court in relation to a dispute arising from a licensing agreement subject to arbitration.
A global real estate investment management and advisory firm
Successfully represented a global real estate investment management and advisory firm in two Japanese litigations concerning its collection of the asset management fees of more than JPY500 million arising out of a real estate investment deal involving a complex taxation scheme.
A Japanese auto components supplier
Acted for a Japanese auto components supplier in a US litigation brought by a US government agency alleging claims of US$175 million.
A large US multinational in a JCAA arbitration
Successfully represented a large US multinational in a JCAA arbitration against a Japanese company arising out of breaches of a distribution and licensing agreement.
An executive of a leading Japanese manufacturing company
Acted for an executive of a leading Japanese manufacturing company in connection with US Department of Justice antitrust investigations.
A mega solar project in Japan
Successfully settled a dispute arising out of a mega solar project in Japan in favor of an American solar mounting system manufacturer through a construction mediation before a Japanese court.
Several major consumer finance companies
Represented several major consumer finance companies in nationwide mass consumer litigation in Japan. Successfully won two Japanese Supreme Court decisions in 2011 and two Japanese Supreme Court decisions in 2017
- Supreme Court Judgment of March 22, 2011, 236 shumin 225
- Supreme Court Judgment of July 8, 2011, 237 shumin 159
- Supreme Court Judgment of July 24, 2017, 71 minshu 6-969
- Supreme Court Judgment of December 19, 2017, H28 ju 1797
Talks
- 'Resolving Domain Name Disputes－25 Years of JP-DRP: Where Brands, Trademarks, and the Internet Intersect', co-hosted by Japan Network Information Center and Japan Intellectual Property Arbitration Center - January 2026
- 'Differences in Arbitral Practice in Japan and Abroad', hosted by CIArb YMG Japan Chapter - May 2023
- 'Law and Culture in North Asian Arbitration', hosted by ICC YAF - May 2022
- 'International Arbitration Training (Intermediate Level): Practice and Key Points from the Perspective of Arbitral Institutions', e-Learning Material of Japan International Dispute Resolution Center - April 2021
- 'Strategies for International IP Dispute Resolution During and After COVID-19', co-hosted by Japan Commercial Arbitration Association and WIPO Arbitration and Mediation Center - February 2021
- 'Japan/Asia Update: Recent Developments in International Arbitration and Dispute Resolution', hosted by ICDR Young & International - January 2021
- 'Key Points of International Arbitration and International Mediation: What You Need to Know Before Drafting Dispute Resolution Clauses', hosted by Nagoya Chamber of Commerce & Industry - December 2020
- 'Basics of International Arbitration and International Mediation: Flexible Dispute Resolution Mechanisms in With / After COVID-19 Era', hosted by Engineering Advancement Association of Japan - October 2020
- 'International Mediation Webinar, Post COVID-19: The New Normal for International Dispute Resolution', co-hosted by Japan Commercial Arbitration Association and Japan International Mediation Center - October 2020
- 'Resolving International Intellectual Property and Technology Disputes Outside of Courts: WIPO Mediation and Arbitration', WIPO Arbitration and Mediation Center - July 2020
- 'Arbitration and Mediation: To improve commercial disputes processing by Vietnam and Japan', co-hosted by Vietnam International Arbitration Center and Research Center for Sustainable Peace of The University of Tokyo - June 2020
- 'APRAG Conference 2020', co-hosted by Thailand Arbitration Center and Asia-Pacific Regional Arbitration Group - January 2020
- '5th IPBA Arbitration Day', co-hosted by Inter-Pacific Bar Association and Japan International Dispute Resolution Center - November 2019
External publications
- JP-DRP Case Review Report (2026), Japan Network Information Center - March 2026
- Japan Chapter, Independent Film & Television Alliance 2021 Arbitration Award Enforcement Guide, 4th Edition - October 2021
- Case Studies on International Mediation of Intellectual Property Disputes: Key Takeaways from Actual Cases, JCA Journal - May 2020
- Arbitrability of Patent Validity Disputes in Japan—Japan as an International IP Arbitration Hub, A.I.P.P.I. - January 2020
- Arbitrability of Patent Validity Disputes: For Enhanced Use of International Arbitrations in Japan, JCA Journal - May and June 2019
- How to Select An Arbitrator in International Commercial Arbitration: Major Considerations and Due Diligence, Business Law Journal - January 2016
- New Japanese Arbitration Case Law: The Osaka District Court's Pro-Arbitration Ruling, HK45/HKIAC Newsletter, 6th Edition - October 2015 (co-author)
- A Comparative Study: Is The Singapore International Commercial Court a Rival of Singapore Arbitration?, Business Law Journal - June 2015 (co-author)
- A Nightmare? When You are Caught in Parallel Proceedings: Utilization of Anti-Suit Injunctions and Anti-Arbitration Injunctions in Common-Law Jurisdictions, Business Law Journal - March 2015 (co-author)
- Key Factors for Japanese Companies to Consider in Selecting an Arbitration Institution, Business Law Journal - November and December 2012 (co-author)
Admissions
- Japan (Dai-Ichi Tokyo Bar Association)
Education
- Waseda University, Graduate School of Law LL.M. in Intellectual Property Law (2019)
- University of Oxford MJur (2014)
- The Legal Training and Research Institute, Supreme Court of Japan Diploma (2009)
- Waseda University B.A., Psychology (1999)
Memberships
- Chartered Institute of Arbitrators (MCIArb, CIArb Accredited Mediator)
- Japan Association of Arbitrators (JAA)
- Japan Association of Industrial Property Law
- The Copyright Law Association of Japan
- The Law and Computers Association of Japan
Languages
- English
- Japanese
- German
Withers History
- Joined 2026