This excerpt taken from the DCM 20-F filed Jun 25, 2009.
Under the Corporation Law, Japanese joint stock corporations (kabushiki kaisha) above a certain size whose shares are transferable without the approval of such corporations, including the Company, may elect to structure their corporate governance system to be either that of a company with a board of corporate auditors (kansayakukai secchigaisha) or that of a company with committees (iinkai secchigaisha). The Company is currently a company with a board of corporate auditors.
As a company with a board of corporate auditors, the Company is not required under the Corporation Law to have any outside directors on its board of directors. The tasks of auditing the performance of its directors and auditing the Companys financial statements are assigned to the Companys corporate auditors, who are separate from the Companys directors. All corporate auditors must meet certain independence requirements under the Corporation Law. Under the Corporation Law, at least one half of a companys corporate auditors are required to be outside corporate auditors who must meet additional independence requirements. An outside corporate auditor is defined as a corporate auditor who has never served as a director, accounting councilor, executive officer, manager or any other employee of the Company or any of its subsidiaries.