Joseph Rochefort

Joseph Rochefort was a United States Navy officer and cryptanalyst who led the Station HYPO codebreaking unit at Pearl Harbor during the Second World War. His team worked on the Japanese naval code JN-25 and combined cryptanalysis with traffic analysis and operational intelligence.

Rochefort’s group correctly identified “AF” as Midway and helped Admiral Chester Nimitz prepare the ambush that produced the American victory in June 1942. Despite that success he was soon transferred away from codebreaking, and full official recognition of his contribution came only much later.

In Jeff Shaara’s The Eagle’s Claw, Admiral Chūichi Nagumo leads the Japanese carrier force, while Chester Nimitz commits his limited ships on the basis of intelligence produced by Joseph Rochefort and the codebreakers at Station HYPO. In Jeff Shaara’s To Wake the Giant, In Hawaii, Joseph Rochefort and other intelligence officers try to interpret incomplete signals.