Germany’s plan for her attack on Western Europe in May 1940 was based entirely on blitzkrieg. Germany’s plan was to avoid a frontal assault on the Maginot Line – the very nature of which would negatively impact the manoeuvrability required by blitzkrieg – and to attack Belgium and France via the Ardennes, an area considered extremely difficult to cross by tanks by both the French and British. The Germans made an assumption that an attack on the Netherlands would be swift and successful; they also assumed that the Belgium Army would also crumble with due speed. Hence their planning was directed towards the French and British armies.
France and Britain based their plans on the assumption that Germany would use a modernised version of the Schlieffen Plan when attacking west. This meant, so the Allies believed, that the primary target was the capital city, Paris. Therefore, it was assumed that the main thrust of the German attack would be through central Belgium to Ostend and that the attack would then sweep south to Paris. To counter this, the British and French had devised a plan whereby both their forces would advance into Belgium and Holland to support the armies of both these countries and to protect the vital North Sea ports. The theory was that the German army would falter as a result of the defensive line put in place by the Allies and, exhausted by their attempts to break this line, would be ripe for an Allied attack.
Ironically, the Allied ‘version’ of the German plan was nearly correct. But this was a plan put together in October 1939. In February 1940, the Germans changed their plan probably because the Allies knew of ‘Plan Yellow’ as a result of a German plane crashing in Belgium in January 1940 – a copy of the plan was on board. After this, Hitler approved of a plan to change ‘Plan Yellow’ – something that General von Manstein had long argued for.
Manstein’s idea was the opposite to ‘Plan Yellow’ in that the roles of Army Groups A and B were to be reversed. Army Group A, commanded by von Rundstedt, was to spearhead the attack through the Ardennes. Manstein believed that to destroy the Allied front, German troops would have to drive through the Allies between Sedan and Namur. After this, they would drive straight to the sea at Abbeville and encircle the BEF and the French 1st and 7th armies. So instead of driving south to Paris, Manstein believed that the main push of the German army should be north-west – away from Paris.
Manstein’s plan included passing over to Army Group A one army (the VI) from Army Group B. Army Group B would be used in the attack to draw forward the BEF and French left wing forward into Belgium thus alleviating the pressure on Army Group A’s attack in the Ardennes. Army Group A was also given seven out of the ten armoured divisions available to the Germans. Parachute units were handed over to Bock’s Army Group B to take vital targets in Belgium and Holland, and also to cause confusion and chaos in both countries.
Manstein’s plan had three major issues:
Could German forces cross the Ardennes, which many military analysts had viewed as nearly impossible?
Could they cross the River Meuse swiftly?
Could German forces fight against the expected French counter-attack in the Somme region?
The success of the German attack depended on what blitzkrieg needed for success – speed and surprise. If both occurred during an attack, then the confusion and chaos that would ensue, would play into the hands of the attackers.
One of the great ironies of the plan was that it concentrated German forces on the weakest point of the Allied defence. Allied planning believed that a German attack would be via north Belgium and the Maginot Line. Therefore, the Allies weakest defence was on the Meuse line, south of Namur – the place where German forces were most concentrated. Against the massive German force that attacked in this sector were the 2nd and 9th French armies, both of which were comparatively weak as they contained a large number of reservists.
While Manstein’s plan was bold, it also took into account the destructive nature of blitzkrieg and the fear that would develop around it. Manstein believed that his plan would lead to the implosion of the French and British armies. He was to be proved correct.