Guderian first served as the commander of the XIX Corps in the invasion of Poland. He personally led the German forces during the Battle of Wizna and Battle of Kobryn testing his theory against the reality of war for the first time. In the Invasion of France, he personally led the attack that traversed the Ardennes Forest, crossed the Meuse River and broke through the French lines at Sedan. During the French campaign, he led his panzer forces in rapid blitzkrieg-style advances and earned the nickname "Der schnelle Heinz" (Fast Heinz) among his troops.[11] Guderian's panzer group led the "race to the sea" that split the Allied armies in two, depriving the French armies and the BEF in Northern France and Belgium of their fuel, food, spare parts and ammunition. Faced with orders from nervous superiors to halt on one occasion, he managed to continue his advance by stating he was performing a 'reconnaissance in force'. Guderian's column was famously denied the chance to destroy the Allied beachhead at Dunkirk by an order coming from high command.In 1941 he commanded Panzergruppe 2, also known as Panzergruppe Guderian, in Operation Barbarossa, the German invasion of the Soviet Union, receiving the 24th award of the Oak Leaves to his Knight's Cross of the Iron Cross on 17 July of that year. From 5 October 1941 he led the redesignated Second Panzer Army. His armoured spearhead captured Smolensk in a remarkably short time and was poised to launch the final assault on Moscow when he was ordered to turn south towards Kiev.He protested against Hitler's decision and as a result lost the FŸhrer's confidence.[citation needed] He was relieved of his command on 25 December 1941 after Fieldmarshal GŸnther von Kluge, not noted for his ability to face up to Hitler,[citation needed] claimed that Guderian had ordered a withdrawal in contradiction of Hitler's "stand fast" order.He was eventually recalled to service and appointedChief of the General Staff when it was to late and had become hopeless.528pp inc. 37maps, battle plans, photos, 25 appendices. Foreword by B.H. Liddell Hart.