Executive Team

Masayuki Yamakawa
Representative Chairman of the Board/M.D.
  • 1989
    B.M., Faculty of Medicine, Tottori University
  • 1993
    Founded Seishin Plastic and Aesthetic Surgery Clinic Co., Ltd. (Retired)
  • 2007
    Founded THE CLINIC Tokyo (Retired)
  • 2015
    Founded SerialIncubate Co., Ltd. (Incumbent Representative Director)
    Founded CellSource Co., Ltd. (Retired)
  • 2016
    Founded Tokyo Knee Osteoarthritis Clinic (Retired)
  • 2022
    Director, CellSource Co., Ltd.
  • 2024
    Chairman of the Board, CellSource Co., Ltd.
  • 2025
    Representative Chairman of the Board (Incumbent), CellSource Co., Ltd.
Takashi Sawada
Representative Director and CEO
CellSource Co., Ltd.
  • 1981
    Joined ITOCHU Corporation
  • 1998
    Vice President, Fast Retailing Co., Ltd.
  • 2003
    Founded Kiacon Corporation
    Representative Director and President , Kiacon Corporation
  • 2005
    Founded Revamp Corporation
    Representative Director and President , Revamp Corporation
  • 2016
    Representative Director and President, FamilyMart Co., Ltd.
  • 2021
    Representative Director and Vice Chairman, FamilyMart Co., Ltd.
  • 2022
    External Director, CellSource Co., Ltd.
  • 2022
    Representative Director, Lotte Ventures Japan Co., Ltd.
  • 2024
    Director (Incumbent), Lotte Ventures Japan Co., Ltd.
  • 2024
    Representative Director and CEO (Incumbent), CellSource Co., Ltd.
Masato Tsumamoto
Director and CXO
  • 2005
    Graduated from the Faculty of Human Development, Kobe University
  • 2005
    Joined Sumitomo Corporation
  • 2007
    Studied at Saint Petersburg State University in Russia
  • 2011
    Assigned to the Plastun office in Russia
  • 2015
    Founder/Representative Director and CEO, CellSource Co., Ltd.
  • 2022
    Outside Director (Incumbent), Ai ROBOTICS INC.
  • 2024
    Representative Director and CXO , CellSource Co., Ltd.
  • 2024
    Director and CXO (Incumbent), CellSource Co., Ltd.
Yuka Shimada
External Director
  • 1996
    Joined Pasona Inc.
  • 2002
    Acquired M.A. in Social-Organizational Psychology from Columbia University Graduate School, New York, United States
  • 2014
    Director, Unilever Japan Holdings K.K. (currently Unilever Japan Holdings G.K.)
  • 2018
    Founded YeeY Inc. Representative Director (Incumbent), YeeY Inc.
  • 2020
    Founded dialogue, Inc. Representative Director (Incumbent), dialogue, Inc.
  • 2021
    General Manager, HR & General Affairs Division, Unilever Japan Holdings G.K.
  • 2022
    Representative Partner (Incumbent), NOTONO G.K.
  • 2022
    Representative Director (Incumbent), Promotion Council for Well-being in Japan
  • 2023
    Outside Director (Incumbent), dip Corporation
  • 2025
    External Director (Incumbent), CellSource Co., Ltd.
Takeshi Amemiya
Director (Full-time Audit & Supervisory Committee Member)
  • 1986
    Graduated from the Faculty of Economics, Kyoto University
  • 1986
    Joined ITOCHU Corporation
  • 1999
    Joined Japan Online Securities Co., Ltd.
  • 2008
    CFO & Executive Director, kabu.com Securities Co., Ltd. (Mitsubishi UFJ e-Smart Securities Co., Ltd.)
  • 2017
    CFO & Director, CellSource Co., Ltd.
  • 2023
    Director (Full-time Audit & Supervisory Committee Member) (Incumbent), CellSource Co., Ltd.
Tsuneyasu Ozaki
External Director (Audit & Supervisory Committee Member)
  • 1994
    The Legal Training and Research Institute of Japan
  • 1996
    Public Prosecutor Appointment
  • 1997
    Fukuoka District Public Prosecutors Office
  • 1999
    Special Investigation Department, Tokyo District Public Prosecutors Office
  • 2003
    Administrative Litigation Division, Litigation Bureau, Ministry of Justice
  • 2004
    Office of Administrative Procedure, Planning and Coordination Division, Administrative Management Bureau, Ministry of Internal Affairs and Communications
  • 2005
    Resignation from the Prosecutors Office/Attorney Registration
  • 2008
    Partner, Nishimura & Asahi (now Nishimura & Asahi, Foreign Law Joint Enterprise)
  • 2014
    External Auditor (Incumbent), Tosoh Corporation
  • 2019
    Audit & Supervisory Board Member, CellSource Co., Ltd.
  • 2023
    External Director (Audit & Supervisory Committee Member) (Incumbent), CellSource Co., Ltd.
  • 2025
    OZAKI BUSINESS LAW OFFICE Attorney at Law (Incumbent)
Kumi Fujisawa
External Director (Audit & Supervisory Committee Member)
  • 1989
    Graduated from Faculty of Human Life Science, Osaka City University
  • 1995
    Founder/President & Representative Director, IFIS Japan Ltd.
  • 2004
    Executive Director (Incumbent), the Investment Trusts Association, Japan
  • 2011
    Public Governor (Incumbent), Japan Securities Dealers Association
  • 2013
    External Director, the Shizuoka Bank, Ltd.
  • 2013
    Representative Director, Sophia Bank Ltd.
  • 2014
    External Director, Toyota Tsusho Corporation
  • 2018
    Director (Incumbent), Japan Professional Football League
  • 2020
    Obtained a master’s degree from the Graduate School of Sport Sciences, Waseda University
  • 2021
    External Director, CellSource Co., Ltd.
  • 2022
    Chairperson (Incumbent), Institute for International Socio-Economic Studies, Ltd.
  • 2022
    Outside Director (Incumbent), Shizuoka Financial Group, Inc.
  • 2023
    External Director (Audit & Supervisory Committee Member) (Incumbent), CellSource Co., Ltd.
  • 2024
    Outside Director (Incumbent), Mercari, Inc.
Kaoru Hosoda
Executive Officer and COO/General Manager of Contract Processing Business Division
  • 2009
    Graduated from the Faculty of Economics, Keio University
  • 2009
    Joined Sumitomo Corporation
  • 2020
    Assigned to the Kyiv office in Ukraine
  • 2022
    Joined CellSource Co., Ltd.
  • 2024
    Executive 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
  • 2015
    Graduated from the Faculty of Law, The University of Tokyo
  • 2015
    Joined McKinsey & Company
  • 2022
    Joined Shiseido Company, Limited
  • 2024
    Joined CellSource Co., Ltd
  • 2024
    Executive Officer and CSO/General Manager of Corporate Strategy Division (Incumbent), CellSource Co., Ltd.
Tomohiro Iga
Executive Officer/General Manager of Corporate Division
  • 1994
    Graduated from the Faculty of Commerce and Management, Hitotsubashi University
  • 1994
    Joined The Long-Term Credit Bank of Japan, Limited(currently known as SBI Shinsei Bank, Limited)
  • 2003
    Joined Kiacon Corporation
  • 2005
    Joined Revamp Corporation
  • 2014
    Joined Fourth Valley Concierge Corporation
  • 2021
    Joined amana inc.
  • 2023
    Representative Director, amana inc.
  • 2024
    Joined CellSource Co., Ltd
  • 2024
    Executive Officer/General Manager of Corporate Division (incumbent), CellSource Co., Ltd.