The Black Chamber Exhibit

This exhibit details the checkered career of Herbert O. Yardley (1889-1958), who headed the highly secret MI-8, or the "Black Chamber." Working for the Army and the State Department in the 1920s, MI-8 in New York broke the diplomatic codes of several different nations, including Japan. The decrypts were used by the U.S. Secretary of State, Charles Evans Hughes, to improve his diplomatic position during the Washington Naval Conference of 1921-22. He appeared to be outsmarting the Japanese to obtain a more favorable agreement on naval capital ships, when actually he was reading their negotiating position every day before he went into the bargaining sessions. In 1929 the State Department closed down MI-8, and a disappointed Yardley published The American Black Chamber, which revealed to the world what his unit had done. Needless to say, the Army, which continued codebreaking, was not amused. And the Japanese, for their part, changed their code systems.