Joseph Rochefort: Unsung Hero of Midway Island Victory

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If you’ve seen the 2019 feature movie, Midway, you might recall the character of a cryptologist named Rochefort, whose unit singularly supported the U.S. fleet during the battle for that island. The movie version of Rochefort wore slippers and a bathrobe over his uniform, as did the man in real life, who, during this intense situation, sometimes went days without bathing.

Joseph John Rochefort was born in Dayton, Ohio, and enlisted in the U.S. Navy in 1918, lying that his birth year was 1898 to appear almost 21 and eligible for the service. He was still in high school at the time in Los Angeles, California, and left without getting a diploma.

He attended the Stevens Institute of Technology, receiving a commission as an ensign after graduation. Rochefort’s tours ashore included cryptanalytic training; a stint as second chief of the Department of Naval Communications’ newly created cryptanalytic organization from 1926 to 1929; training in the Japanese language from 1929 to 1932; and a two-year intelligence assignment in San Diego from 1936 to 1938. Until 1941, Rochefort spent 9 years in cryptologic or intelligence-related assignments and 14 years at sea in positions of increasing responsibility.

In early 1941, Rochefort headed to Hawaii to become Officer in Charge of “Station Hypo” (“H” for Hawaii in the navy’s phonetic alphabet at the time) in Pearl Harbor. Rochefort hand-picked many members of Hypo’s team, and it contained the navy’s best cryptanalysts, traffic analysts, and linguists. The team was assigned to break the Japanese navy’s most secure cypher system, the Flag Officers Code.

After the Japanese attack on Pearl Harbor, Rochefort and Station Hypo, with assistance from both British cryptographers at the Far East Combined Bureau and Dutch cryptographers, were eventually able to read enough of Japanese naval communications to provide daily intelligence reports and assessments of Japanese force disposition and intentions. During May 1942, Rochefort reviewed, analyzed, and reported on as many as 140 decrypted messages a day, which went to the highest-ranking fleet commanders. Rochefort would often go for days without emerging from his bunker, where he and his staff spent upwards of 12 hours a day working to decode Japanese radio traffic.

Station Hypo maintained that the next Japanese attack would be in the Central Pacific and convinced Admiral Chester W. Nimitz, who commanded the U.S. Pacific Fleet, that it would perhaps be in the Aleutian Islands, Port Moresby in Papua New Guinea, or even the west coast of the United States. One of the Station Hypo staff, Jasper Holmes, suggested faking a failure of the water supply on Midway Island and using an unencrypted emergency warning to provoke a Japanese response. This would determine if Midway was a target.

Now a captain, Rochefort took the idea to Edwin T. Layton, the chief intelligence officer for Nimitz. Layton and Rochefort went way back, having met on a voyage to Tokyo when both men were sent to learn Japanese. Layton proposed the idea to Nimitz, who approved. The garrison commander was told by submarine cable to immediately radio in “plain language” an emergency request for water, indicating that an explosion in the water desalination system left them only enough water for two weeks.

The Japanese bit. Within hours, they broadcast instructions to load additional water desalination equipment, confirming Rochefort’s analysis. Layton noted that the instructions also “produced an unexpected bonus.” They revealed that the attack would happen before mid-June. An intercepted message of May 26, 1942, with orders for two destroyer groups escorting invasion transports, nailed down the date of the attack as either June 4 or 5. During the week before Nimitz issued his final orders, “decrypts were being processed at the rate of five hundred to a thousand a day.” The battle raged from June 4 to 7. The work of Rochefort and his team allowed the United States to virtually ambush Japanese naval forces, turning the tide of the war in the Pacific.

When Nimitz recommended Rochefort for a Navy Distinguished Service Medal, Rochefort said that it would only “make trouble.” Others have suggested that Rochefort received no official recognition during his lifetime because he was scapegoated by the brother of Rear Admiral Joseph Redman, who complained about the operation of the Hawaii station. The complaint resulted in Rochefort’s reassignment from cryptanalysis to commanding a floating dry dock at San Francisco. Rochefort never served at sea again. The lack of recognition for Rochefort was an outrage to some. 

Rochefort headed the Pacific Strategic Intelligence Group in Washington after the war. He died in Torrance, California, in 1976, at age 76.

Posthumously, he was awarded the Navy Distinguished Service Medal in 1985 and the Presidential Medal of Freedom in 1986. Also that year, he received the President’s National Defense Service Medal, the highest military award during peacetime, for his support to the Battle of Midway. In 2000, he was inducted into the Hall of Fame of the National Security Agency’s Central Security Service.