German Deception Plan
The German deception plan, like all successful deception plans, contained enough truth to make it plausible. The purpose of the plan was to convince the Allies that the German Army’s greatest fear was Allied penetration and breakthrough in the northern area near Koln and a subsequent drive to the Rhine River. Therefore, they wanted the Allies to believe that the German Army was preparing for this possibility by moving units into the area for an eventual counterattack. In the south a smaller, less capable force was being assembled in the Eifel Region to contain the Allied penetration there.
The German Army was very serious about not letting the Allies discover the intent of the build-up. At Army headquarters a separate war diary was maintained, and no one with knowledge of the plan was allowed to travel by air. Additionally, the strict German Staff procedures precluded anyone without proper ‘need to know’ to see anything more than needed to do his job. Therefore, most of the staff officers transferring units and stockpiling supplies did not know why they were doing it. More than one was to question the seemingly illogical movements. At the operational level, success or failure of the deception plan revolved around both the 5.Panzer Army and the 6.Panzer-Army.
The 6.PA under SS-Obergruppenführer Joseph Sepp Dietrich moved into an open plain northwest of Koln and purposely practiced lax security measures. The increased road and rail movement was done in daylight and only partially hidden. Additionally, German engineers conducted extensive repairs on roads and railroads with no attempt at concealment. Radio traffic was increased to subordinate divisions, some civilian evacuations were begun, and additional antiaircraft units were moved into the area and given extra allotments of ammunition to convince Allied airmen of the importance of the region. All this was done with one intention: to convince Allied intelligence that these were the prudent movements of an army preparing to defend its homeland with a counterattack if necessary. The other key unit in the plan was the 5.PA, an experienced armor unit commanded by General der Panzertruppen Hasso Ecard von Manteuffel. It had to be moved from the vicinity of the French Lorraine Department, opposite Patton, to the north in such a way as not to arouse Allied suspicions. It was brought up and put into the line near Aachen with very little secrecy in what was interpreted by western intelligence as clearly a logical military maneuver to reduce the span of control of one commander, Erich Brandenberger and his 7.Army.
While in the line, the headquarters of the 5.PA kept up the normal radio traffic of a unit preparing for the defense. Under this cover, subordinate units rotated out of the line for refitting. This was only the first step for the 5.PA. It next had to be pulled out of the line in secrecy as the date for the offensive approached. On schedule, the headquarters of the 15.Army (previously operating in the Netherlands) secretly relieved the 5.PA and assumed the title ‘Gruppe von Manteuffel’. Normal movements and radio traffic continued. The 15.Army was then in turn relieved by the headquarters of the 25.Army which began calling itself the 15.Army. The final step in this evolution was the creation of a completely bogus 25.Army with all necessary radio traffic and fictitious order of battle (Charles B. McDonald). To make it even more plausible, the 25t.Army’s radio traffic suggested that it was forming in the vicinity of the 6.PA for defensive operations.
One final major command shift had to be concealed: Field Marshal Walter Model’s Army Group B. It was assumed that any Allied intelligence officer or commander would recognize that Model’s front, extending over 150 miles, was overextended. Therefore, the creation of Army Group H in the north without any attempt at secrecy would not seem unusual. Significantly, this shift left Model, the man Hitler entrusted to carry out the plan, responsible for the sector from Aachen to the Ardennes. Once the final date for the attack was determined, the tactical portion of the deception plan began. The three-day movement into the Eifel had to be protected at all costs, and the German Army carried it out with great success. The average German soldier had learned since Normandy the importance of camouflage. Allied air superiority dictated that his very survival depended on it. Therefore, the strict security measures put into effect in the Eifel were second-nature to him, and he executed them without question. The thick forest of the Eifel region lent itself to camouflage. Small, insignificant villages that were ignored by Allied aerial reconnaissance could hold large numbers of vehicles and men. All movement into these villages was done at night; and no movement on the streets, even by individual soldiers, was allowed in daylight. Cooking fires were not permitted. Special security detachments patrolled the region to observe the size of vehicle parks and the overall implementation of security measures. (They had the authority to relieve commanders on the spot). The radio blackout by ground units was total.
Though the German soldier was not told of the plan and his role in it until the night before the attack, German commanders were worried about deserters who might give away details of the plan that could be pieced together by Allied intelligence officers. Since the rugged nature of the Eifel lent itself to desertions, ‘Volksdeutschers’ (ethnic Alsatians and others) , had been previously culled from front line units and would not be returned until the night before the attack (They were not allowed to go on patrols even then in case they learned more than they should). The concern these ‘Volksdeutschers’ caused is evidenced by the fact that Hitler himself required a report every twenty-four hours listing by name every deserter. Of note, there were only five deserters along the entire front in December. In addition to deserters, senior army commanders worried about prisoners of war, especially the higher ranking officers. Already there were several German generals in POW camps in England. If captured, these officers must not be allowed to give away any information of substance. These concerns, though real at the time, proved groundless. For example, one German division commander captured by the Allies produced completely confusing information. (It is not known if he did it by design or whether he, too, was deceived)(Sir Kenneth Strong, Intelligence at the Top (New York: Doubleday and Company, 1969).
Only a few trusted officers were permitted to conduct ground reconnaissance, and combat patrols were limited to defensive measures in search of Allied patrols. Artillery fires were restricted to the established normal patterns, and only guns that had been on the line could conduct registration fires. Movement into the line was restricted to 12 miles the first night. Then, over the next two nights, the units moved to six miles and finally to two. Recognizing the noise made by tanks, German armored units were kept further back. On the last two nights as tanks and other mechanized units moved forward, straw was laid on the roads, and German aircraft flew low over the area to muffle the sound. (Charles B. McDonald) Finally, on the night of December 15, the German soldiers were told the true mission and what was expected of them. Most of the front line units were then given hot meals and bottles of schnapps and told to prepare. The discipline required by the individual soldier to mask the movements of units into the line was extraordinary. It was constantly drummed into the German soldier that his greatest fear would be Allied aircraft. This was not just hyperbole, as the German commanders believed it also. Therefore, it was not difficult to achieve the secrecy demanded of an operation of this magnitude. It was survival, and everyone understood it.
What the Allies Knew
Much has been written since the war on the Allies’ intelligence failure. Many of the writings have been by former intelligence officers who were directly involved in the campaign. Most, if not all, claim to have predicted in some way the German attack and try to shift the blame to the commanders. Therefore, much of the information on what the Allies knew is suspect. One thing is certain, however. There is enough blame to go around.
Reliance on ULTRA
There were many Allied intelligence success stories in the war, but one of the most important was the breaking of the German radio codes. These codes were produced by a machine called Enigma and were used by both the German military and the diplomatic corps. The Germans thought these codes to be unbreakable and relied on them throughout the war, attributing any possible compromises of information to other sources such as spies. By the fall of 1944, the Allied code-breaking effort had yielded tremendous results. The Allies were reading enough of the military messages to have a reasonable idea of the German order-of- battle and operational plans. A system was devised whereby Allied operational commanders and their intelligence officers received all intercepted messages pertinent to their area of operations, generally within twenty-four hours of intercept. The translated and interpreted messages sent to the Allied commanders bore the overall codename of ULTRA.
The decoding of the German Enigma system for ULTRA was not merely a triumph of engineering or mathematical theory; it was the cumulative achievement of an extraordinary group of cryptologists, analysts, and decoders—many of whom history has unjustly consigned to the margins. The foundations were laid by the Polish pioneers Marian Rejewski, Jerzy Różycki, and Henryk Zygalski, whose early breakthroughs made later British successes possible. At Bletchley Park, figures such as Alan Turing, Gordon Welchman, Dilly Knox, and John Herivel developed the conceptual and technical tools that enabled sustained penetration of Enigma traffic.
Yet the real weight of ULTRA rested on the shoulders of the decoders—the meticulous, anonymous specialists who transformed theory into actionable intelligence. Among them were Mavis Batey, whose work on Abwehr keys proved critical; Joan Clarke, a brilliant cryptanalyst of the highest rank; Margaret Rock, a master of reconstructing daily keys; and Peter Twinn, the first British analyst to break an operational Enigma message. Even individuals such as Geoffrey Tandy, originally misassigned but indispensable for preserving fragile intercepts, played a vital supporting role.
Their collective labor—tireless, unseen, executed under absolute secrecy—allowed ULTRA to reveal enemy intentions, safeguard Allied forces, and shorten the war. Generals may have directed the campaigns, but it was the quiet precision of these decoders that made decisive victories possible. History often forgets their names; ULTRA does not.
This successful effort became a two-edged sword that was not apparent until after the battle. So successful was this program that by December 1944, Allied commanders had come to trust ULTRA so exclusively that they relied on it to provide both enemy capabilities and intentions. Generally, this information was unambiguous and did not always require detailed analysis. When Hitler directed that all messages regarding the planning for the offensive not be transmitted by radio, the Allies were deprived of much of this ‘unambiguous’ data. There was one area, however, that was unaffected by this directive but which the Allies failed to fully recognize and exploit. Regardless of Hitler’s concerns, the logistic and deployment preparations could not be accomplished in a sufficiently timely fashion without the radio transmission of messages. Here, ULTRA provided considerable amounts of data. By late October, the Allies knew that the Germans were forming a formidable reserve that would contain several Panzer divisions. Many Allied intelligence officers did believe that this reserve would be built around the newly created 6.Panzer-Army, but what ULTRA didn’t tell them was the purpose for this reserve and how it would be used. More importantly, ULTRA did not tell them that this reserve was neither for Model nor von Rundstedt, but for Hitler.
Throughout October and November, ULTRA was providing the Allies a rich diet of information on troop movements, both into and out of the front lines. ULTRA intercepts also provided the Allies with considerable information on the train movements into the region, as much of the dispatching and tracing was done by radio. Additionally, there were a number of messages from army headquarters requesting Luftwaffe air cover on detraining and marshalling areas. By the end of November however, Allied intelligence officers seem to have made up their minds that all this movement and logistic resupply was for the assumed German counterattack in the north. The German deception plan reinforced this analysis, regardless of the additional information ULTRA furnished. Another good source of ULTRA intercepts was the Luftwaffe. The German Air Force never stopped using radio transmissions to any great extent, and the Allies were reading much of their traffic. In particular, the Luftwaffe on several occasions referred to the ‘Jageraufmarsch’ (the coming operation) when requesting serviceability reports on aircraft or providing information to air defense units.
Reading Luftwaffe intercepts also provided an unambiguous indication of the transfer of air force squadrons to the north and west in addition to the formation of a new headquarters for fighters in the central region. A message intercepted on the November 19, informed German air defenses of the build-up of fighters in Western Germany and directed them to take extra precautions not to shoot down German planes (Robert S. Whitlow, ULTRA Intelligence Procedures—IX Air Force (Washington: US Department of the Army, 1945). On November 21, a Luftwaffe message referred to the ‘final’ decision of Reichsmarschall Herman Goering that fighters in the west scheduled to fly in the upcoming ‘operation’ were not to be fitted with bomb racks. Instead, these racks were to be stored away from the planes and kept in good condition. On December 1, another Luftwaffe message said that it is certain that the Allies had recognized the increased concentration of fighters in preparation for the ‘Jageraufmarsch’ and to prepare for Allied bombing of these concentrations. These messages, and many others like them, were ambiguous in the sense that the ‘upcoming operation’ could have been either an offensive operation or a counterattack. But Allied intelligence officers were already convinced that a German counterattack was likely since it supported the overall defensive scheme as they saw it. Consequently, the Luftwaffe messages were read in that context. Even an intercepted message from a German ground unit for aerial reconnaissance of the Meuse River from Liège to Givet did not seem to have raised any undo concerns.
Additionally, ULTRA was providing considerable information from lower echelon units reporting, almost daily, of chronic fuel shortages. These messages outlined curtailed flying hours and other measures Luftwaffe units had to take to save fuel. By relying on these intercepts from the lower echelon units, Allied intelligence officers made the logic inference that the entire German Air Force had these same fuel shortage problems. As a consequence, no one anticipated that fuel could or would be saved at the strategic level. ULTRA also provided diplomatic information that was available not only to Washington but front line units as well. The more telling of these diplomatic messages was in mid-November from the Japanese Ambassador, Baron Oshima, to his government. It was composed after the ambassador had had lunch with von Ribbentrop. During the lunch von Ribbentrop continued to assure the ambassador that things were going well for Germany and that they planned to stay on the offensive until the end. The German also stated that an offensive in the west was planned, although he gave no dates. It is unclear how intelligence officers in Washington and Europe viewed this intercept, as few make any reference to it. It is likely, however, that many thought that it was nothing more than the German attempting to allay the fears of an ally.
It is possible that the effect of ULTRA on the minds of the intelligence officers and commanders had a negative reinforcing role. Previously, commanders viewed what they received from ULTRA in the context of how they saw the battlefield and to corroborate information from other sources. Montgomery, for instance, used ULTRA to reinforce information about German armor units on his front and could immediately see any changes in patterns. But prior to Ardennes this corroborative effect, because of German deception, was absent. In fact, the decline in ULTRA traffic was viewed by some, especially Bletchley Park, as a positive sign that victory could be imminent (Ronald Lewin, ULTRA Goes to War (New York: McGraw-Hill Book Company, 1978). Without ULTRA the Allies did not seem to view information from other sources with the same sense of urgency or importance.