| July 2004 |  | Rio Law Accountant Office, Judicial Scrivener Hideki Hayashi Office, and Mami Sugiyama Tax Accountant Office start business together, as "Rio Law Accountant Office" | 
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| January 2007 |  | Judicial Scrivener Corporate Rio Partners (Representative then: Hideki Hayashi) founded * The representative as of June 2011 is Hiroaki Ishii.
 Tax Accountant Corpporate Rio Partners (Representative: Mami Sekine) founded
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| October 2007 |  | Changed Office name from Rio Law Accountant Office to Rio Partners SOGO Office | 
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| June 2008 |  | Legal Professional Corporate Rio Partners (representative: Hiroshi Minami & Kenichiro Komiya) founded |