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Having been established in 1984 Oaza Nagashima Zaisanku have built on the extensive knowledge of our founding partners to give clients support and expert advice on major business transactions and complex issues from a legal perspective. Having built a reputation as leaders in Mergers & Acquisitions, Private equity, venture capital and Securities law, both in Japan and internationally, we focus on medium to large scale transactions, including acquisitions, public takeovers and company restructuring as well as company sales. Here at Oaza Nagashima Zaisanku, even for the most complex projects you can rest assured that you will receive extensive support and expert advice from an experienced, international team, with a proven track record. Over the past decade it has become increasingly common in Japan to find firms consolidating and expanding into over a hundred attorneys as in the United States.

In contrast, our firm has continued to emphasize traits absent from many larger firms by offering the highest quality services to our clients – speed, flexibility, detailed knowledge and experience and personal service. Over the years we have also formed working relationships with various overseas law firms, accountants and specialized consultants, with whom we work closely on client matters and which add another layer of flexibility, speed and quality that we can offer to our clients. Today, at the start of the 21st century, as borderless, economic globalization increases ever more quickly, and as the degree and speed of technical innovation increases as well, the problems clients face are increasingly complex. We are committed to meeting these complex technical, legal, and business needs and providing the highest quality service to our clients.


  • General Corporate

    Our office offers a full range of general corporate legal services to Japanese and foreign businesses including corporate establishment and administrative filings, permit and approval applications, shareholder and board of director’s guidance, contract drafting and negotiations, labor issues, compliance, and corporate mergers, reorganization, and dissolution. We place special emphasis on careful drafting and individual attention in our agreements in order to not only reduce our clients’ risks, but to avoid future litigation and legal disputes.

  • International Transactions

    Our office provides full transactional services from contract drafting and negotiation to regulatory compliance for cross border transactions between Japanese and overseas companies. We offer a full array of transactional experience including licensing, distribution, finance, mergers and acquisitions, and joint ventures. We have established a system under which we can offer our clients not only our own services and expertise, but also the expertise, when needed, of affiliated firms in other countries. With companies doing business internationally, there inevitably comes the risk of litigation in other countries. To deal with this risk, we offer our clients extensive experience representing Japanese and foreign businesses in international litigation and arbitration.

  • Intellectual Property

    With publication in July 2002 of its Outline of National Intellectual Property Strategy and subsequent legislation such as the Intellectual Property Basic Act, the Japanese government has moved to promote intellectual property as a twenty-first-century national priority. With this new emphasis, Japanese businesses have come to place greater emphasis on IP development and protection than ever before. Our office offers a wealth of experience in providing the most relevant advice regarding patents, know-how, and copyrights and in drafting and negotiating license and technology transfer and protection agreements tailored to each client’s needs. In addition to extensive experience in representing clients in patent litigation in Japan and the United States, we also provide representation in patent invalidation procedures at the Japanese Patent Office as well as for import restrictions with the Japanese customs service. We provide all of our IP services in affiliation with registered patent attorneys and technical specialists, and with full and complete understanding of the technologies at issue, so that we can provide our clients with services fully responsive to their legal, technical and business needs.

  • Project Finance

    Our office has extensive experience representing clients in overseas natural resource and infrastructure development projects including full project finance drafting and negotiating.

  • Mergers & Acquisitions

    We offer full support for mergers and acquisitions from advice, study and drafting of potential project schemes to due diligence, contract drafting and negotiation, and administrative filings.

  • Antitrust/Trade Law

    Whether in mergers, joint ventures, licensing, distribution relationships or other business activities, companies must keep in mind potential antitrust violations. Our office provides full antitrust reviews of our clients’ plans and we are able to incorporate our experience not only into representing our clients in antitrust matters but in designing ventures and business relationships that avoid antitrust concerns in the first place. We also have extensive experience representing Japanese businesses involved in dumping actions in the United States and the European Union.

  • Tax

    It is inevitable that there will be various tax implications to doing business between Japanese and non-Japanese companies. With the assistance of our affiliated accountants and tax consultants our office provides optimum tax planning regarding tax laws in Japan and in those countries that have concluded tax treaties with Japan.

  • Employment Law

    Employment and labor matters are essential for all businesses. It is especially essential for foreign businesses operating in Japan to have optimal advice regarding Japan’s labor rules and regulations. Our office provides advice to Japanese and non-Japanese businesses regarding employment agreements and regulatory compliance as well as handling disciplinary, termination, and other personnel matters. We also provide representation in court and arbitration proceedings related to the resolution of employment disputes.

  • Other Conflict Resolution

    In order to provide proper service and advice to our corporate clients in their day-to-day management, we offer advice in a wide array of matters including ordinary civil disputes, bankruptcies, medical practice cases, and administrative matters. We also provide representation in arbitration, mediation and other alternative dispute resolution venues. Although the majority of our clients are businesses, we also provide services to individual clients seeking to fulfill our social duty as attorneys by providing pro bono representation.


Takaaki Nagashima / Partner


  • 9/1976 – 4/1977 George Washington University National Law Center Georgetown University Law Center Consortium Independent Researcher
  • 9/1975 – 8/1976 George Washington University National Law Center M.C.L. in American Practice
  • 4/1971 – 4/1973 The Supreme Court of Japan Legal Research and Training Institute,Tokyo
  • 4/1968 – 3/1971 Tokyo Metropolitan University Research Center for Social Sciences
  • 4/1964 – 3/1968 Chuo University Bachelor of Law

Legal Experience:

  • 3/2012 – present Visiting Professor of Hiroshima University
  • 4/1984 – present Partner in Oaza Nagashima Zaisanku, Tokyo, Japan
  • 2/1981 – 3/1984 Partner in law firms in Tokyo, Japan, specializing in international commercial and financial transactions
  • 9/1977 – 1/1981 Associate with Mudge Rose Guthrie & Alexander, New York, New York, and De Bant, Van-Hecke, Van Gerven, Lagae & Van Bael, Brussels, Belgium
  • 4/1973 – 7/1975 Associate with Kikuchi Law and Patent Office, Tokyo, Japan

Bar Admissions:

  • Japan: The Japan Bar and the Second Tokyo Bar, 1973
  • Washington, D.C.: The Washington, D.C. Bar, 1978; the United States District Court for the
  • District of Columbia, 1978; and the United States Court of Appeals for the District of Columbia Circuit, 1978.
  • New York: The New York Bar, 1979; and the United States District Courts for the Southern and Eastern Districts of New York.
  • United States Customs Court: The Bar of the United States Customs Court, 1978; and the United States Court of Customs and Patent Appeals, 1979.

Akira Oaza / Partner


  • 1981 – 1982 Harvard Law School Master of Law, American Law
  • 1974 – 1980 Paris University, Faculty of Law Doctor Degree EC Antitrust Law
  • 1973 – 1974 Paris University, Faculty of Law Preparatory Degree for Doctor Degree French Commercial Law
  • 1971 – 1973 Supreme Court of Japan Legal Research and Training Institute, Tokyo Law Clerk for Tokyo District Court Judge
  • 1966 – 1970 Tokyo University, Faculty of Law, Tokyo Bachelor of Law: Japanese Law

Legal Experience:

  • 1984 – present Partner at Oaza Nagashima Zaisanku Tokyo, Japan
  • 1984 Schlumberger Limited Legal Department Paris, France
  • 1982-1983 Schlumberger Limited Legal Department New York, USA
  • 1979 – 1981 Cleary, Gottlieb, Steen & Hamilton Brussels, Belgium

Bar Admissions:

  • The Japan Bar and the Tokyo Bar, 1973
  • The New York Bar, 1984
  • The Paris Bar, 1992

Tadahiko Zaisanku / Partner


  • 1995 Bachelor of Law, University of Tokyo
  • 1996 – 1998 Supreme Court of Japan, Legal Research and Training Institute

Legal Experience:

  • 2005 – present Associate, Nagashima & Hashimoto
  • 1998 – 2004 Associate, Taguchi Sogo Law Office, Tokyo, Japan

Bar Admissions:

  • The Japan Bar and the Daiichi Tokyo Bar Association, 1998

Legal Teaching:

  • Asia University (2002)
  • Tokai University (2004)


Robert L Cohen / Of Counsel

Expertise in the areas of banking and financial services, public utility regulation, government and public relations, and alternative dispute resolution.

Bar Admissions:

Mr. Cohen is admitted to practice before U.S. District Court for the Eastern District of Michigan, United States District Court for the Western District of Michigan and Michigan Court of Appeals.

Patrick A Bradford / Of Counsel

Expertise in traditional M&A and private equity transactions. Mr. Bradford is one of the few corporate transactional lawyers with extensive experience structuring and executing distressed transactions.

Bar Admissions:

Mr. Bradford is admitted to practice: District of Columbia, Court of Appeals of Maryland, U.S. Bankruptcy Court for the District of Maryland, U.S. District Court for the District of Columbia, U.S. District Court for the District of Maryland.

Leonard Colamarino / Of Counsel

Experience includes litigation at the state and federal levels, including the New York City Court of Appeals and the United States Court of Appeals.

Bar Admissions:

  • United States Court of Appeals for the Second Circuit
  • United States District Court for the Southern and Eastern Districts of New York
  • Member of the District of Columbia Bar
  • Member of the State Bar of New York


Michael T Brennan / Associate
Bar Admissions:

Yuichiro Yasutomo / Associate
Bar Admissions:
The Japan Bar and the Second Tokyo Bar, 2010

Eita Asabuki / Associate
Bar Admissions:
The Japan Bar and the Second Tokyo Bar, 2010

Christopher J Campa / Associate
Bar Admissions:

Sei Hasegawa / Associate
Bar Admissions:
The Japan Bar and the Second Tokyo Bar, 2013

Nobuhiro Nonaka / Associate
Bar Admissions:
Japan Patent Attorneys Association, 2005
Japan Bar and the First Tokyo Bar, 2014

Ofer Sharone / Associate
Bar Admissions:


Oaza Nagashima Zaisanku 3-1-1, Nakasakurazuka,
Toyonaka Shi, Osaka Japan