Promoted to General der Panzertruppen and on the outbreak of war was given command of the Nineteenth Corps, which he led in the Polish Campaign. For the battle of France he was given a Panzer group, and his brilliant handling was a perfect demonstration of the concept of blitzkrieg -rapid armored breakthrough, supported by air power, on a narrow front- which he had propagated in his writings. Vintage 3.5 x 5.5 Hoffmann postcard photo, signed in fountain pen, 'Guderian.' In fine condition, with some light contrast to signature. RRAuction COA.