Joseph Rochefort

United States state institutions 1900–1976 ○ Natural causes

Head of Station HYPO who identified the Japanese objective "AF" as Midway

Born in Dayton, Ohio, he joined the navy while still at school, trained in cryptanalysis and Japanese, and in 1941 became officer in charge of Station HYPO at Pearl Harbor. In spring 1942 his unit concluded that "AF" in Japanese naval traffic was Midway and that the blow would come in early June, and confirmed it with a fake message that Midway was short of water. OP-20-G in Washington and the Chief of Naval Operations, Ernest King, argued for other targets and mid-June, but Nimitz followed HYPO and laid his ambush at Midway. After the battle King rejected Nimitz's recommendation for a medal, and Rochefort was moved out of codebreaking to command a floating dry dock. He received the Navy Distinguished Service Medal only posthumously, in 1986.

Also known as: Joseph John Rochefort