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by Lori S. Stewart, USAICoE Command Historian
MAGIC CONTRIBUTES TO D-DAY SUCCESS
On 10 November 1943, the Second Signal Service Battalion’s Morse code interceptors listened to a lengthy message sent by the Japanese ambassador in Berlin to the Foreign Affairs Ministry in Tokyo. The information in the message was a windfall for the Allies’ planning for the upcoming invasion of northern France.
In the late morning of 10 November 1943, Pvt. Leonard Mudloff sat in front of his typewriter in northern Virginia listening to radio transmissions out of Berlin. Mudloff was one of several intercept operators on duty that morning at the Vint Hill Farms Station listening post. Near lunchtime, he tuned in to a repetitive communication: “Urgent Message…Berlin calling Tokyo.” Over the next couple of days, successive shifts of operators copied the lengthy message that followed and sent it to the analysts at Arlington Hall Station, the Signal Security Agency’s (SSA) headquarters, for further analysis. This was the normal process for PURPLE, the U.S. Army’s code name for the Japanese diplomatic messaging system. The intelligence gleaned from PURPLE decrypts was code-named MAGIC, and indeed, the information the incoming message contained was similarly astonishing.
The message Private Mudloff intercepted that morning had been sent by Oshima Hiroshi, a general in the Japanese Imperial Army and the Japanese ambassador to Berlin. Oshima, a close associate of Hitler’s, had direct access to Nazi war plans and national policy. Through his voluminous messages, he kept the Foreign Affairs Ministry in Tokyo apprised of events and conditions in Germany, such as munitions production and experiments with jet planes and rocket bombs, and hinted at things like Japan’s desire to obtain uranium.
Most importantly, they filled a gap in the Allies’ communications intelligence. While the Allies had broken the German military code, they had not yet broken the German diplomatic code. Fortunately, not realizing the Allies had broken the Japanese diplomatic code, Oshima’s messages provided the Allies with uncommon insight into Germany’s plans as well as Hitler’s perceptions of the Allies’ plans. General George C. Marshall, the Army’s chief of staff, stated in a September 1944 letter, “Our main basis of information regarding Hitler’s intentions in Europe is obtained from Baron Oshima’s messages from Berlin reporting his interviews with Hitler and other officials to the Japanese Government….”
The message intercepted on 10 November 1943 outlined Oshima’s late October tour of Germany’s Atlantic Wall fortifications spanning the coast of continental Europe and the western coast of Norway. His trip report clearly outlined Germany’s preparations to prevent an Allied invasion along the French coast. He included precise locations of every German division, their strength and weapons, their available reserve forces, as well as obstacles built to prevent Allied soldiers from reaching the beaches. He also revealed that, due to Hitler’s belief any Allied landing at a site other than Pas de Calais would be a feint, no German troops would be removed from Pas de Calais to reinforce other beaches.
General Dwight D. Eisenhower later attributed the success of the June 1944 D-Day operations, in part, to Oshima’s 10 November message. When SSA intercepted the report, the Allies were in their final planning stages for Operation OVERLORD, the invasion of Normandy. With this windfall of information, the Allies revised the original plan to account for the German defenses. Furthermore, continual monitoring of the message traffic over the first six months of 1944 convinced the Allies Germany had not uncovered the truth behind Operation FORTITUDE, the deception operations leading up to D-Day.
After the war, Oshima Hiroshi was captured and convicted for war crimes. He was sentenced to life in prison but was paroled in 1955. He died in 1975 never knowing he contributed so much intelligence to the Allied cause. Private Mudloff was promoted and continued his service until discharged as a technical sergeant in 1944.
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| Date Taken: | 11.08.2024 |
| Date Posted: | 11.08.2024 13:58 |
| Story ID: | 484976 |
| Location: | US |
| Web Views: | 29 |
| Downloads: | 0 |
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