Executive Team

Masayuki Yamakawa
Representative Chairman of the Board/M.D.
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1989B.M., Faculty of Medicine, Tottori University
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1993Founded Seishin Plastic and Aesthetic Surgery Clinic Co., Ltd. (Retired)
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2007Founded THE CLINIC Tokyo (Retired)
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2015Founded SerialIncubate Co., Ltd. (Incumbent Representative Director)
Founded CellSource Co., Ltd. (Retired) -
2016Founded Tokyo Knee Osteoarthritis Clinic (Retired)
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2022Director, CellSource Co., Ltd.
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2024Chairman of the Board, CellSource Co., Ltd.
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2025Representative Chairman of the Board (Incumbent), CellSource Co., Ltd.

Takashi Sawada
Representative Director and CEO
CellSource Co., Ltd.
CellSource Co., Ltd.
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1981Joined ITOCHU Corporation
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1998Vice President, Fast Retailing Co., Ltd.
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2003Founded Kiacon Corporation
Representative Director and President , Kiacon Corporation -
2005Founded Revamp Corporation
Representative Director and President , Revamp Corporation -
2016Representative Director and President, FamilyMart Co., Ltd.
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2021Representative Director and Vice Chairman, FamilyMart Co., Ltd.
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2022External Director, CellSource Co., Ltd.
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2022Representative Director, Lotte Ventures Japan Co., Ltd.
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2024Director (Incumbent), Lotte Ventures Japan Co., Ltd.
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2024Representative Director and CEO (Incumbent), CellSource Co., Ltd.

Masato Tsumamoto
Director and CXO
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2005Graduated from the Faculty of Human Development, Kobe University
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2005Joined Sumitomo Corporation
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2007Studied at Saint Petersburg State University in Russia
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2011Assigned to the Plastun office in Russia
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2015Founder/Representative Director and CEO, CellSource Co., Ltd.
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2022Outside Director (Incumbent), Ai ROBOTICS INC.
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2024Representative Director and CXO , CellSource Co., Ltd.
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2024Director and CXO (Incumbent), CellSource Co., Ltd.

Yuka Shimada
External Director
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1996Joined Pasona Inc.
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2002Acquired M.A. in Social-Organizational Psychology from Columbia University Graduate School, New York, United States
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2014Director, Unilever Japan Holdings K.K. (currently Unilever Japan Holdings G.K.)
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2018Founded YeeY Inc. Representative Director (Incumbent), YeeY Inc.
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2020Founded dialogue, Inc. Representative Director (Incumbent), dialogue, Inc.
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2021General Manager, HR & General Affairs Division, Unilever Japan Holdings G.K.
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2022Representative Partner (Incumbent), NOTONO G.K.
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2022Representative Director (Incumbent), Promotion Council for Well-being in Japan
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2023Outside Director (Incumbent), dip Corporation
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2025External Director (Incumbent), CellSource Co., Ltd.

Takeshi Amemiya
Director (Full-time Audit & Supervisory Committee Member)
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1986Graduated from the Faculty of Economics, Kyoto University
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1986Joined ITOCHU Corporation
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1999Joined Japan Online Securities Co., Ltd.
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2008CFO & Executive Director, kabu.com Securities Co., Ltd. (Mitsubishi UFJ e-Smart Securities Co., Ltd.)
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2017CFO & Director, CellSource Co., Ltd.
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2023Director (Full-time Audit & Supervisory Committee Member) (Incumbent), CellSource Co., Ltd.

Tsuneyasu Ozaki
External Director (Audit & Supervisory Committee Member)
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1994The Legal Training and Research Institute of Japan
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1996Public Prosecutor Appointment
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1997Fukuoka District Public Prosecutors Office
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1999Special Investigation Department, Tokyo District Public Prosecutors Office
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2003Administrative Litigation Division, Litigation Bureau, Ministry of Justice
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2004Office of Administrative Procedure, Planning and Coordination Division, Administrative Management Bureau, Ministry of Internal Affairs and Communications
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2005Resignation from the Prosecutors Office/Attorney Registration
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2008Partner, Nishimura & Asahi (now Nishimura & Asahi, Foreign Law Joint Enterprise)
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2014External Auditor (Incumbent), Tosoh Corporation
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2019Audit & Supervisory Board Member, CellSource Co., Ltd.
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2023External Director (Audit & Supervisory Committee Member) (Incumbent), CellSource Co., Ltd.
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2025OZAKI BUSINESS LAW OFFICE Attorney at Law (Incumbent)

Kumi Fujisawa
External Director (Audit & Supervisory Committee Member)
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1989Graduated from Faculty of Human Life Science, Osaka City University
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1995Founder/President & Representative Director, IFIS Japan Ltd.
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2004Executive Director (Incumbent), the Investment Trusts Association, Japan
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2011Public Governor (Incumbent), Japan Securities Dealers Association
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2013External Director, the Shizuoka Bank, Ltd.
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2013Representative Director, Sophia Bank Ltd.
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2014External Director, Toyota Tsusho Corporation
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2018Director (Incumbent), Japan Professional Football League
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2020Obtained a master’s degree from the Graduate School of Sport Sciences, Waseda University
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2021External Director, CellSource Co., Ltd.
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2022Chairperson (Incumbent), Institute for International Socio-Economic Studies, Ltd.
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2022Outside Director (Incumbent), Shizuoka Financial Group, Inc.
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2023External Director (Audit & Supervisory Committee Member) (Incumbent), CellSource Co., Ltd.
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2024Outside Director (Incumbent), Mercari, Inc.

Kaoru Hosoda
Executive Officer and COO/General Manager of Contract Processing Business Division
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2009Graduated from the Faculty of Economics, Keio University
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2009Joined Sumitomo Corporation
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2020Assigned to the Kyiv office in Ukraine
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2022Joined CellSource Co., Ltd.
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2024Executive Officer and COO/General Manager of Contract Processing Business Division (Incumbent), CellSource Co., Ltd.

Yuta Hayashi
Executive Officer and CSO/General Manager of Corporate Strategy Division
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2015Graduated from the Faculty of Law, The University of Tokyo
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2015Joined McKinsey & Company
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2022Joined Shiseido Company, Limited
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2024Joined CellSource Co., Ltd
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2024Executive Officer and CSO/General Manager of Corporate Strategy Division (Incumbent), CellSource Co., Ltd.

Tomohiro Iga
Executive Officer/General Manager of Corporate Division
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1994Graduated from the Faculty of Commerce and Management, Hitotsubashi University
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1994Joined The Long-Term Credit Bank of Japan, Limited(currently known as SBI Shinsei Bank, Limited)
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2003Joined Kiacon Corporation
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2005Joined Revamp Corporation
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2014Joined Fourth Valley Concierge Corporation
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2021Joined amana inc.
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2023Representative Director, amana inc.
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2024Joined CellSource Co., Ltd
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2024Executive Officer/General Manager of Corporate Division (incumbent), CellSource Co., Ltd.