Atsumi & Sakai was formed in 1994 as Atsumi & Usui before adopting its current name in 2010 following the acquisition of a practice group from TMI Associates. The firm has close to 150 lawyers and offices in Tokyo, London and Frankfurt. It was the first Japanese law firm to register as a joint venture between Japanese and foreign lawyers in 2005, and in 2013 it formed a joint venture with the German law practice of Markus Janssen. In 2021, the firm launched an affiliate office in New York, Atsumi & Sakai New York. In 2025, the firm launched an affiliate office in the port city of Osaka.
The firm is best known for its structured finance and securitisation work but also has a strong project development and finance practice.
Throughout the research cycle, the firm continues to advise multiple multi-million-dollar financing transactions in the banking, capital markets, M&A and project sectors. With a focus on project finance, acquisition finance and asset finance, the firm advises clients across a wide range of financing transactions and services.
A major focus of the firm's capital markets practice is to provide guidance on structuring, SPC formation, and related regulatory issues to originators, arrangers, trustees and institutional investors.
Over the past year, the firm bolstered its capabilities in banking and finance, corporate M&A, and project sectors with the hiring of lists of partners including Atsushi Tabata, Akiko Hosokawa, Makiko Harada, Christopher Hodgens and Akiko Hosokawa.
Key clients of the firm include Tokyo Metropolitan Government, Financial Services Agency, HyAS & Co., Sumitomo life Insurance, Oasis Management Company, Sega Sammy Holdings, Mitsubishi Research Institute, and The Japan Research Institute.
"What we value is the ability to provide timely and accurate support, based on a deep understanding of our business and position, even amid differing legal systems in Japan and overseas." (Banking and finance client)
“Detailed service, prompt advice." (M&A client)
"They are individually specialized, have a good understanding of business, and can cover a wide range of areas as a team."(M&A client)
"Legal knowledge and client-first attitude." (Project development client)
"Responsive. Clear advice. Approachable. Not overly 'legalistic’." (Project development client)
"We have a good relationship partner – Daniel Jarrett. Daniel leads us to various practice areas on Japanese law matters. Daniel's quality control is very effective. Good team and wide variety of expertise." (Project finance client)
"English fluency; expertise in M&A."
"He always seeks the best solution for his clients."
"He and his team provided qualified legal services on due diligence, contract document review, legal advice, and labor relations regarding M&A and healthcare services. Additionally, he manages and supervises his team's work well to control service quality."
"Responsive. Clear. Manages team and deadlines."
"Ms. Oikawa has experience being seconded to our company, and she has a deep understanding of our business and the legal issues associated with it. Based on this understanding, she provides precise legal advice on individual matters from the client’s perspective, with a strong sense of empathy."
