The Battle of Britain Five Months That Changed History, May—October 1940 by James Holland (z-lib.org).epub

helped by a particularly vicious winter that even the Führer could tell was
no help to offensive plans. Indeed, the excuse of poor weather came to
Halder and von Brauchitsch’s rescue time and time again; by 10 May, the
attack date had been postponed no fewer than twenty-nine times. Even
better, Hitler was also now considering an attack in Denmark and Norway
first, before an offensive in the west. The Führer had recognized during the
winter months the importance of Norway as the only route through which
much-needed Swedish iron ore could reach Germany. This in turn meant
the offensive in the west would take place in early summer, when
conditions were far more favourable. Furthermore, rather than revealing
German plans, the Mechelen incident had paradoxically shown Allied
intentions instead, and that was something that could be used to the
Germans’ advantage.
And that wasn’t all. War games at the beginning of February had shown
Halder that Guderian’s and von Manstein’s plans for a deep panzer thrust
might just work after all. Finally, the French, it seemed, had been very slow
to respond to recent German regrouping movements along the front:
intelligence suggested they had taken between ten and fourteen days to pick
this up. Thus if the main French defences through the Ardennes could be
reached in under that time, the French could be caught out. ‘Surprise may
now be regarded as assured,’ he noted with confidence in his diary after a
February Führer conference.
The methodical, careful, and rather unimaginative original plan would
probably avoid any quick defeat. In fact, it would almost certainly lead to
the long drawn-out attritional war that those veterans of the First World War
so dreaded. The von Manstein–Guderian go-for-broke plan, on the other
hand, might lead to a very quick and disastrous defeat. Yet, it might – might
– just give them the emphatic victory they needed: certainly, Halder now
realized, it was the only plan that had a possible chance of success. Thus by
the end of February, when Halder submitted his latest plans for Case
Yellow, he had completed his dramatic volte face: Army Group B would
noisily thrust into Holland and northern Belgium with the support of the
majority of the Luftwaffe, while the panzers of Army Group A would hurry
through the Ardennes and attack the French across the Meuse. With luck,
the Allies would be coaxed into a trap, rushing forward to meet the northern
thrust, while the main German attack burst through the back door around