Sanno Park Tower 12F (Reception) and 14F,
11-1, Nagatacho 2-chome, Chiyoda-ku,
Tokyo 100-6114, Japan

Tokyo Metro Ginza Line: G06 Tameike-sanno Station, Exit 7 (directly accessible through the second basement)

Tokyo Metro Nanboku Line: N06 Tameike-sanno Station, Exit 7 (directly accessible through the second basement)

Tokyo Metro Chiyoda Line: C07 Kokkai-gijido-mae Station, Exit 5 (3 minutes’ walk)

Tokyo Metro Marunouchi Line: M14 Kokkai-gijido-mae Station, Exit 5 (10 minutes’ walk through Chiyoda Line platform)

Senior Associates

Mitsuya Kosaka

Mitsuya Kosaka

TEL +81-3-5511-3225 / FAX +81-3-5511-3258

Bar Association
Japan (2014)


The University of Tokyo (LL.B)
Chuo Law School (J.D.)
Admitted in Japan (Dai-ni Tokyo Bar Association)
Ushijima & Partners

Special lecturer at Faculty of Commerce of Chuo University

Passed the Information Technology Engineering Examination (Information Security Management Examination), 2019


“The Amended Act on the Protection of Personal Information and Business Practice” (SEIBUNSHA, June 2017)

Articles, etc.

“[Series] Start Today! Information Security Measures #1: A Grounding in Information Security,” (November 1, 2021 issue of Romu Jijo)

“Points When Introducing Electronic Contracts Based on Their Features” (“Intellectual Property Management” magazine, August 20, 2021)

“Utilization of ‘Examples of Efforts for Preventing Corporate Scandals’ Aimed at Effective Whistleblowing System” (“BUSINESS LAWYERS,” February 18, 2020)

“What is Certification Concerning Internal Reporting Systems? The Advantages of Obtaining the Certification and the Standards for the Certification” (BUSINESS LAWYERS, August 6, 2019)

“Specific Points for Obtaining Certification Concerning Internal Reporting Systems” (BUSINESS LAWYERS, August 6, 2019)

“Specific Measures (Such as Whistleblowing System) and Practical Points for Early Detection of Misconduct” (“BUSINESS LAWYERS,” May 8, 2019)

“Points for Practically Reviewing a Whistleblowing System Based on Guidelines” (“BUSINESS LAWYERS,” May 8, 2019)

“Characteristics and points of the sale of business by auctions adopted by Toshiba in the sale of its semiconductor memory business” (“BUSINESS LAWYERS,” June 27, 2017)

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Lectures Given

“Matters to Examine and Matters to Note in Introducing E-Contracts” (Legaledge, November 25, 2021)

“Matters to Note Regarding Publication of Scandals and Practical Measures to Prevent Information Leaks in Relation to Working from Home” (FRONTEO, June 12, 2020)

“Patterns of How Misconduct/Scandals Are Discovered in Real Cases and Specific Measures to Discover Them Promptly” (FRONTEO, April 27, 2020)

“Seminar on Measures Addressing the Amended Act on the Protection of Personal Information by Small and Medium Enterprises” (Ome Chamber of Commerce and Industry, May 16, 2017)

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