Mayumi Hongo

Atsumi & Sakai - Japan




Rising star partner




Practice areas:

Project development
Project finance

Ms. Hongo is a Partner at Atsumi & Sakai. She has the unique experience of working as a lawyer specializing in infrastructure after working for about 10 years for one of Japan's leading heavy industry manufacturers. She has long experience working on legal issues with project members at the forefront of the company, so she is able to be close to her clients as she aims to resolve issues from a practical point of view.
In recent years, Japan has seen an increase in inbound factory construction from overseas, and she was involved as the main counsel in the construction of a factory for the world's leading semiconductor manufacturer that attracted much attention in Japan.
She is also one of the few lawyers who can support overseas companies from the perspective of the Construction Business Act, which is a major barrier for overseas construction companies. She is familiar with domestic and foreign construction model forms, such as FIDIC, and her experience working for the Ministry of Foreign Affairs makes her an excellent negotiator with ministries and local governments.

  • Main counsel for the construction of a plant in Japan for the world's largest semiconductor manufacturer.
  • Advised Taiwanese semiconductor companies on the Construction Business Act to speed up the process of obtaining construction licenses including negotiations with the Ministry of Land, Infrastructure, Transport and Tourism and local government.
  • Advised an overseas power generation manufacturer entering the Japanese market from the perspective of overcoming differences between FIDIC and other international model forms and Japanese model forms.
  • Negotiated with local government on behalf of a company that could have been charged with violations of the Construction Business Act resulting in the company not being charged with any violations.
  • Supported for overseas companies entering the Japanese construction market from the perspective of overcoming regulations set out in the Construction Business Act.

  • Project development
  • Project finance


  • Construction and materials
  • Energy
  • Government and public policy
  • Industrials
  • Transport

  • Dai-ichi Tokyo Bar Association


  • Sophia University (LL.B. in International Legal Studies, 1994)
  • The University of Tokyo, School of Law (J.D., 2007)