This was a US deception operation designed to persuade the Germans to delay any reinforcement of the southern shoulder of the salient they had driven into the Allied line in 'Wacht am Rhein' by suggesting that the movement of Lieutenant General George S. Patton’s movement to the north was considerably slower than in fact it was (16/30 December 1944).
'Ardennes' was effected largely by 'special means' (double agents), in this case two Frenchmen in the area of Metz supposedly working for the German army’s radio service. The concept of 'Ardennes' was for these two men, who had been captured and supposedly 'turned' after being parachuted into the area of Metz and Verdun, to report on the US divisions which moved through their areas later than was in fact the case. These reports were to be confirmed by radio simulation of the US formations in locations farther to the south than those which they had in fact reached.
'Ardennes' was severely degraded by the all-too-common laxity of US radio security, of which the worst was that of the military police. Of the first two of Patton’s divisions to move to the north, Major General Hugh J. Gaffey’s 4th Armored Division and Major General Horace L. McBride’s 80th Division, the former was detected swiftly by the German radio intelligence branch despite US efforts to confuse this service by duplicating the real division’s transmissions by faked items in 'Kodak' on 22/23 December, but the latter achieved tactical surprise. An effort to depict Major General Paul W. Baade’s 35th Division waiting in reserve while it was actually moving up was defeated by the leaks of the military police radio net, which as so often in the past gave true information to the Germans. Greater success attended the depiction of Major General Frank L. Culin’s 87th Division in 'Metz I' (28/31December) as still being in Metz even as it moved to the north.