Nagashima Ohno & Tsunematsu
One of Japan's leading full-service law firms and a member of the country's traditional Big Four.
Last updated August 22, 2026
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Overview
Nagashima Ohno & Tsunematsu is a major Japanese full-service law firm headquartered in Kioichō, Chiyoda, Tokyo. Commonly abbreviated as NO&T and also known as N&T, it advises corporations, financial institutions, investors, public companies and other organizations on a broad range of domestic and cross-border legal matters. Its work spans corporate and commercial law, finance, capital markets, mergers and acquisitions, competition law, dispute resolution, employment, intellectual property, real estate and regulatory matters. The firm is generally identified as one of Japan's Big Four law firms. The present firm was created in 2000 through the merger of Nagashima & Ohno and Tsunematsu Yanase & Sekine. Nagashima & Ohno had been established in 1961 and had itself become one of Japan's leading corporate law practices before the merger. Tsunematsu Yanase & Sekine was established in 1987 by lawyers who departed from Blakemore & Mitsuki. The combination brought together two established practices and created a platform with a broader capacity to serve large Japanese companies and international clients. NO&T's client base has included major Japanese banks and financial groups, international investment banks, securities and investment businesses, industrial companies, airlines, energy companies, technology businesses and stock-market infrastructure providers. Publicly cited clients include Bank of Tokyo-Mitsubishi UFJ, Goldman Sachs, GREE, Japan Airlines, JFE Holdings, LaSalle Investment Management, Mizuho Bank, Nomura Holdings, Renault, Sumitomo Mitsui Banking Corporation, Tokyo Electric Power Company, Tokyo Stock Exchange and Yahoo Japan. These relationships illustrate the firm's emphasis on complex corporate transactions, financial services, capital markets, infrastructure, energy and international business. The firm has developed an international presence through its own overseas offices and relationships with foreign firms. It opened a New York office in 2010, following the acquisition or integration of the practice formerly known as Masuda International, and established a Singapore office in 2013. Nagashima & Ohno had previously operated in Singapore from 1993 to 1996. NO&T is also affiliated with Allens Arthur Robinson in Australia and Zhong Lun in the People's Republic of China, supporting work involving those jurisdictions while retaining its Japanese headquarters and identity. The firm's internal organization uses a two-tier partnership model. Associates may become non-equity junior partners after roughly their tenth to twelfth year of practice, while admission as equity-holding senior partners occurs later and is not automatic. This structure distinguishes professional seniority from ownership participation. In a 2013 poll conducted by the Nihon Keizai Shimbun among attorneys and corporate legal departments, partner Hiroshi Mitoma was selected as Japan's best corporate lawyer and partner Hiroki Inoue as Japan's best international lawyer. The firm continues to be positioned as a high-end adviser for sophisticated Japanese and multinational clients.
History
Nagashima Ohno & Tsunematsu was formed in 2000 through the merger of Nagashima & Ohno and Tsunematsu Yanase & Sekine. The merger joined two prominent Japanese legal practices and created a large, full-service firm serving domestic and international businesses. Nagashima & Ohno dated from 1961 and had already been regarded as one of Japan's leading law firms, including as a member of the group commonly described as the country's Big Four. Tsunematsu Yanase & Sekine had been established in 1987 by lawyers who left Blakemore & Mitsuki. The formation of NO&T therefore represented an integration of established corporate-law traditions rather than the creation of a new practice without historical antecedents. The firm's headquarters is in Kioichō, in Tokyo's Chiyoda ward, on the former site of the Legal Research and Training Institute of the Supreme Court of Japan. From this base, NO&T developed a broad practice serving banks, securities firms, investment managers, industrial companies, airlines, energy businesses, technology companies and market institutions. Its publicly identified clients have included Bank of Tokyo-Mitsubishi UFJ, Goldman Sachs, GREE, Japan Airlines, JFE Holdings, LaSalle Investment Management, Mizuho Bank, Nomura Holdings, Renault, Sumitomo Mitsui Banking Corporation, Tokyo Electric Power Company, Tokyo Stock Exchange and Yahoo Japan. International expansion became an important part of the firm's development. Nagashima & Ohno had operated a Singapore office from 1993 to 1996. After the 2000 merger, NO&T established a New York office in 2010, formerly associated with Masuda International, and opened a Singapore office in 2013. The firm also formed affiliations with Allens Arthur Robinson in Australia and Zhong Lun in the People's Republic of China. These arrangements gave clients access to additional jurisdictions while preserving NO&T's Japanese partnership and brand structure. NO&T's service model is built around a wide range of business-law practices, including corporate transactions, finance, capital markets, competition, disputes, employment, intellectual property, real estate and regulatory work. Its clients often require advice combining Japanese law with foreign legal, commercial or regulatory considerations. The firm's partnership system uses two levels: associates can become non-equity junior partners after approximately ten to twelve years of practice, while equity partnership is a later and separate step that is not guaranteed. This arrangement reflects a distinction between professional advancement and ownership in the firm. The firm's professional reputation has also been reflected in external rankings and surveys. In a December 2013 Nihon Keizai Shimbun poll of lawyers and corporate legal departments, partner Hiroshi Mitoma was selected as Japan's best corporate lawyer and partner Hiroki Inoue as Japan's best international lawyer. NO&T remains identified with high-value corporate and financial legal work in Japan and cross-border matters involving Japanese and multinational clients.
- 2013
Singapore office opens
[1]NO&T opens a Singapore office, extending its direct international office network in Asia.
- 2013
Partners receive national lawyer-poll recognition
[1]Hiroshi Mitoma and Hiroki Inoue are recognized respectively for corporate and international legal work in a Nihon Keizai Shimbun poll.
- 2010
New York office opens
[1]The firm establishes a New York presence, formerly associated with Masuda International.
- 2000
Nagashima Ohno & Tsunematsu is formed
[1]Nagashima & Ohno merges with Tsunematsu Yanase & Sekine to create the present firm.
- 1987
Tsunematsu Yanase & Sekine is established
[1]A group of lawyers departing from Blakemore & Mitsuki establishes Tsunematsu Yanase & Sekine.
- 1961
Nagashima & Ohno is founded
[1]Nagashima & Ohno is established and later becomes recognized as one of Japan's leading law firms.
Products and positioning
A leading Japanese full-service business law firm focused on sophisticated corporate, financial, transactional, regulatory and dispute-resolution mandates, with international reach through overseas offices and foreign-firm affiliations.
Legal services
Corporate and commercial law
Advice for companies and other organizations on governance, commercial arrangements, corporate structuring, strategic transactions and general business operations. This practice forms part of the firm's full-service offering for large Japanese and international clients.
Transactional legal services
Mergers and acquisitions
Legal advice on acquisitions, disposals, mergers, investments, joint ventures and other strategic combinations, including matters involving Japanese companies and cross-border counterparties.
Financial legal services
Banking, finance and capital markets
Advice to banks, securities firms, investment managers, issuers and borrowers on financing transactions, securities offerings and other financial-market matters. The firm's client references include major Japanese and international financial institutions.
Dispute-resolution legal services
Dispute resolution
Representation and advice in commercial disputes and other complex contentious matters. The practice complements the firm's transactional work and supports clients facing legal conflicts in Japan and international contexts.
Regulatory legal services
Competition, regulatory and compliance
Advice on competition law, regulatory requirements and compliance issues affecting corporate, financial, infrastructure, energy and other regulated activities.
Industry-focused legal services
Real estate, infrastructure and energy
Legal support for property, infrastructure and energy projects, including the commercial and regulatory dimensions of major assets and operating businesses.
Brand decisions
2013
Expansion into SingaporeStrategyBackground
Singapore served as an important regional center for Asian business and cross-border transactions.
Action taken
The firm opened a Singapore office after Nagashima & Ohno's earlier Singapore operation had ended in 1996.
Aftermath
The new office expanded NO&T's direct regional coverage and complemented its relationships with foreign firms in Australia and China.
2010
Expansion into New YorkStrategyBackground
Growing cross-border work created demand for a direct presence in the United States.
Action taken
NO&T opened a New York office, formerly associated with Masuda International.
Aftermath
The office strengthened the firm's ability to support Japanese clients and international transactions involving the United States.
2000
Merger creating Nagashima Ohno & TsunematsuM&ABackground
Nagashima & Ohno and Tsunematsu Yanase & Sekine were established Japanese corporate-law practices with complementary histories and client bases.
Action taken
The two firms combined to establish Nagashima Ohno & Tsunematsu as a larger full-service practice.
Aftermath
The merger produced a firm identified with Japan's Big Four and positioned it to serve major domestic and international clients across a broader range of legal practices.
Sources1 sources
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