anticipation of a longer campaign. The gained air superiority but suffered far greater losses than the army. Operations on 10 May cost the and by the end of the month of its aircraft had been written off and badly damaged. The concentration of units in the Ardennes was an extraordinary gamble and had the Allied air forces been able to bomb the columns, the advance could have been reduced to chaos. The "audacious" manoeuvre of Army Group A comprised only about twelve armoured and motorised divisions; most of the rest of the German army invaded on foot, supplied from railheads. The Channel coast was a natural obstacle, only a few hundred kilometres from the German border and over such a distance, motorised supply from railheads, over the dense west European road network, was possible and the invaders could live off the land, amidst the highly developed agriculture of western Europe, unlike in Poland where it had been much harder to maintain momentum. Tooze concluded that although the German victory of 1940 was not determined by brute force, the did not rewrite the rules of war or succeed because of the ardour of German soldiers and French pacifism. The odds against Germany were not so extreme as to be insurmountable by better planning for an offensive based on the familiar principles of . The German army managed to concentrate a hugely powerful force at the decisive point but took a gamble of great magnitude, that could not be repeated if the attack failed. When the Germans attempted to repeat the success of 1940 against the Soviet Union in 1941, little was left in reserve. The Red Army had a greater margin of numerical superiority, better leadership and more room for manoeuvre; the Napoleonic principle of the concentration of superior force at the decisive point was impossible for the Germans to achieve. In the 2014 edition of Breaking Point, Doughty described how in a 1956 publication, Fuller wrote that the Battle of Sedan was an "attack by paralyzation" that he had devised in 1918 and incorporated into Plan 1919. Doughty wrote that although the Germans hoped for a quick victory, there is little evidence to support Fuller and that if the military theory later labelled Blitzkrieg was influential in the German officer corps, only those like Manstein and Guderian had fully accepted it. The disagreement between Kleist and Guderian that led Guderian