W Partners


W Partners law firm was founded in February 2018, by the experienced lawyer in the professional filed of laws.


We truly believe that it is critically important to understand our client’s corporate vision and business model to provide our best legal services. We know that all legal issues are closely related to client’s business, therefore we do not deem it is best to provide advice that will only solve the problem without comprehensive view. There is a true benefit to our clients when we thoroughly break down why the issue has occurred and how we can prevent other issues from happening in the future and provide our answers from our professional legal standpoint. This is what we believe is expected in the today’s legal professional industry.

When our clients launch business, they sometimes ask for our advice on the legality of the business model. However, we do not think it is best for our clients if we provide a black or white answer on the legality. We believe that there is a true value in proposing legal and business strategies in such grey zones to make the business happen.

We wish each of our clients to regard our services not as cost but as necessary investment for the success. Our firm name “W Partners” is named after the proximity of the relationship with our clients. First “V” for our clients and the next “V” for our firm. Together, we desire to build an alliance that will lead to “Win”.


Our firm’s services are not limited to domestic affairs, we also handle a wide range of cross-border issues by capitalizing our global network. We cater various legal services ranging from daily legal counseling to M&A, personnel labor, legal compliance and conflict resolution, etc. Particularly, we are experienced in helping foreign-based companies start businesses in Japan. Experts who are proficient in the rapidly-evolving technology field are in the firm as well.

Corporate / M&A

In addition to general corporate legal affairs, we are able to support all aspects including strategic planning of M&A and organizational restructuring, which greatly contributes to strengthening market competing power of our clients. We also provide practical guidance on corporate governance which is gaining importance in the recent market.

Risk and Crisis Management / Compliance

We assist you to respond promptly and properly when you face a critical situation or some risk rises to the surface.

IT / Intellectual Property

We provide hands-on advice on rapidly-advancing technology which requires professional knowledges by our experts.

Competition / Antitrust Law

We provide assistance on competition law / antitrust law, both of which are becoming increasingly important in and outside of Japan.

Labor and Employment

Our experts with broad experience and expertise support you towards proper personnel labor management in accordance with the related laws and regulations.

Finance-related laws / Debt Collection

We assist you regarding finance-related laws and debt collection based on numerous experiences.


We provide high-quality legal services on taxation that is becoming complex and specialized based on our latest knowledge of legal and judicial cases.


In response to puzzling and diversified regulatory laws, we help you with for day-to-day business operation and transitions.

Public Interest Corporations / General Incorporated Associations etc.

We assist in the establishment of Incorporated association, Incorporated foundation (Observation of various regulations and construction of governance structure) and other incorporation of public benefit corporations. We have professionals who used to be executive of such organizations and we are able to support based on our actual experience in the line of service.

Restructuring / Insolvency

We support the early restoration and rebuilding of business in the aspect of laws.

Litigation and other Dispute Resolution

We help to regain legitimate rights to resolve disputes and conflicts.

Personal related Legal Affairs

We also provide professional services in family and inheritance issues, business succession, property trades, leasehold rental, conflict with neighbors, debt consolidation, traffic accidents, criminal cases and all other legal problems.


Managing Partner

Registered as a lawyer (Daiichi Tokyo Bar Association)

Kosuke Mitsumoto


  • Bachelor of Law, Department of Political Science, Faculty of Law, Keio University
  • Master of Science in Public Policy and Management with a Minor in Business Administration, H. John Heinz III School of Public Policy and Management; Collaborative
  • Program with the Tepper School of Business, Carnegie Mellon University
    Juris Doctor, Faculty of Law, Graduate Schools for Law and Politics (School of Law), University of Tokyo

After completing a globally famous graduate school in the field of information technology, he joined IBM Business Consulting Service Co., Ltd. (currently IBM Japan, Ltd.) and belonged to the Technology Strategy group of Strategic Consulting department. As a strategic consultant, he engaged in projects related to organization change, supply chain management, technology strategy and overseas expansion for five years.

After registered as a lawyer, he worked at a law firm in Tokyo. He engaged in multiple projects such as foreign companies entering into Japan, risk and crisis management, regulatory compliance, personnel labor and employment projects, general corporate legal affairs and M&A.


ARK Hills South Tower 16th floor, 1-4-5 Roppongi, Minato-ku, Tokyo, 106-0032

TEL: +813-4405-4959 FAX: +813-6745-4429

You can walk directly from Tokyo Metro Namboku Line-Roppongi 1 chome Station Exit 3


We are hiring professionals who are highly motivated and conform our firm’s philosophy.

For registered lawyers
Those who wish to visit our firm, please send an e-mail with a resume attached at info@wpartnerslaw.com. Please mention "Office visit / recruitment request" in the email.

Law school graduates / Those who passed short-cut exam
Those who wish to visit our firm, please send an e-mail at info@wpartnerslaw.com. Please mention "Office visit / recruitment request" in the email. Please attach your resume and transcript from your university. For those who already graduated from law schools, please attach a transcript from the law school.

About personal information
Personal information (Name, date of birth, address, telephone number, other information that can identify the individuals) acquired by our firm in the recruitment process or firm visits are used for acceptance of applicants, recruitment of applicants, replying to inquiries, etc. We may use these information for data of future recruitment activities at our firm. We do not use such personal information or provide to third parties unless otherwise agreed by the individual or agreed with laws.


Please send you your inquiries to the following email address.