ASEAN Law Forum 2025

She previously lived in Malaysia, Vietnam and Singapore and is fluent in English, Mandarin, Cantonese and Malay. She has extensive experience and local expertise to advise clients from both legal and practical perspective.

She was admitted to the Malaysian Bar in 2013 and is the managing partner of our strategic alliance firm in Malaysia, WM Leong & Co. She is also a partner at Nishimura & Asahi (Singapore) LLP.

Ms. Tomimatsu has extensive experience in the field of international economic law and international arbitration and litigation relating to cross-border business and investment.

She is familiar with EPAs/FTAs (especially in the areas of investment and services, and sustainable development, including labor, environment, and state-owned enterprises), investment agreements/BITs, and international economic law relating to natural resources and energy. She has extensive experience in negotiating international agreements and resolving international economic disputes, and has been involved in the formation of international economic rules and their strategic application in order to ensure fair competition and improve the business environment both in Japan and overseas. She also provides clients with analysis and advice on the formation of rules and their strategic operation and utilization.

With regard to international dispute resolution, she has particular expertise in investor-state dispute settlement procedures (ISDS), international commercial arbitration and mediation, and domestic and international litigation. With regard to foreign investment, utilizing her experience in handling international economic disputes gained at a U.S. law firm, she advises on the prevention of economic disputes in international transactions and business development in foreign countries, as well as on issues to be resolved locally by companies, in particular, those who have suffered or may suffer economic loss due to domestic or foreign discriminatory measures, expropriation and unfair treatment involving the host country of the investment.

She is the author of numerous publications and seminars papers, and frequently presents at conferences on international investment law and international arbitration.