|1964||Graduated from Osaka Prefectural Toyonaka High School|
|1967||Passed the National Bar Exam|
|1968||Graduated from Faculty of Law, the University of Tokyo|
|1970||Completed the Judicial Training(22nd alumni), registered as an attorney at law, and joined Irokawa Law Office|
|1977||Became a partner of Irokawa Law Office|
|2001||Became a chairman of Irokawa Law Office|
Governor, Japan Federation of Bar Associations (April 1995 – March 1996)
Vice-President, Osaka Bar Association (April 1995 – March1996)
Conciliation Board, Osaka District Court and Osaka Summary Court Director of Osaka District Office, Japan Legal Support Center (April 2012 – April 2018)
Outside Auditor, Toyo Aluminium K.K. (June 2006 -)
Outside Auditor, Keyence Corporation (June 2008 – June 2016)
Outside Director, Sumitomo Rubber Industries, Ltd. (March 2009 -)
Outside Auditor, Sekisui Plastics Co., Ltd. (June 2012 -)
Governor and Councilor, Osaka Saiseikai, Social Welfare Organization Saiseikai Imperial Gift Foundation, Inc. (April 2008 -)
Auditor, Nippon Life Saiseikai Foundation (June 2011 -)
Over 40 years have passed since Mr. Kosaka was registered as an attorney at law in 1970. Throughout that time, he has worked at Irokawa Law Office. He believes that he owes his present standing to the many associated client companies and senior colleagues in the office, including Mr. Irokawa, who have fostered his career over the years. Although he primarily focuses on corporate law, he also works in various other fields such as intellectual property, Anti-Monoply Act, and administrative issues faced by local governments. He takes pride in his well-rounded experience. With respect to litigation, he has been engaged in large-scale lawsuits related to drug-induced medical conditions and environmental pollution. In particular, he has dealt with a considerable number of cases related to labor issues and securities transaction.
In recent years, he has focused on consulting services. He endeavors to provide useful advice to help corporate executives exercise their managerial judgment to the greatest possible extent. In addition, he has had an increasing number of opportunities to share his opinions on corporate governance with corporations and other organizations. He also hold positions of corporate outside director and officer for various entities.
For recreation, while he used to play an active role in a tennis club made up of people working in different legal professions, these days he leans more toward golf, at which he has become reasonably proficient. He is also involved in the management of several golf clubs.
Affiliations: Japan Bar Association and Management Lawyers Council