the Germans that the entire Corps was moving north to Flanders. The Canadian Corps was not fully in position until 7 August. To maintain secrecy, the Allied commanders pasted the notice "Keep Your Mouth Shut" into orders issued to the men, and referred to the action as a "raid" rather than an "offensive". Preliminaries Although the Germans were still on the offensive in late July, the Allied armies were growing in strength, as more American units arrived in France, and British reinforcements were transferred from the Home Army in Britain and the Sinai and Palestine Campaign. The German commanders realised in early August that their forces might be forced onto the defensive, though Amiens was not considered to be a likely front. The Germans believed the French would probably attack the Saint-Mihiel front east of Rheims, or in Flanders near Mount Kemmel, while they believed the British would attack along either the Lys or near Albert. The Allies had indeed mounted a number of local counter-offensives in these sectors, both to gain local objectives to improve their defensive positions and to distract attention from the Amiens sector. German forces began to withdraw from the Lys and other fronts in response to these theories. The Allies maintained equal artillery and air fire along their various fronts, moving troops only at night, and feigning movements during the day to mask their actual intent. The German front east of Amiens was held by their Second Army under General Georg von der Marwitz, with six divisions in line (and two facing the French 1st Army). There were only two divisions in immediate reserve. There was some concern among the Allies on 6 August when the German 27th Division actually attacked north of the Somme on part of the front on which the Allies planned to attack two days later. The German division (a specially selected and trained Stosstruppen formation) penetrated roughly into the one-and-a-half-mile front. This attack was made in retaliation for a trench raid by the 5th Australian Division north of the Somme on the night of 31 July, which had taken many prisoners, before the Australian Corps was concentrated south of the river. The German division moved back towards its original position on the morning of 7 August, but the movement still required changes to the Allied plan. To increase the level of surprise still further, the rumble of the approaching tanks