German plan The September Campaign was devised by General
Franz Halder, the
chief of the general staff, and directed by General
Walther von Brauchitsch the
commander in chief of the
German ground forces. It called for the start of hostilities before a
declaration of war, and pursued a doctrine of mass encirclement and destruction of enemy forces. The infantry, far from completely mechanized but fitted with fast-moving artillery and logistic support, was to be supported by
Panzers and small numbers of truck-mounted infantry (the
Schützen regiments, forerunners of the
panzergrenadiers) to assist the rapid movement of troops and concentrate on
localized parts of the enemy
front, eventually isolating segments of the enemy, surrounding, and destroying them. The prewar "armoured idea", which an American journalist in 1939 dubbed
Blitzkrieg, which was advocated by some generals, including
Heinz Guderian, would have had the armour punching holes in the enemy's front and ranging deep into rear areas, but the campaign in Poland would be fought along more traditional lines. That stemmed from conservatism on the part of the German High Command, which mainly restricted the role of armour and mechanized forces to supporting the conventional infantry divisions. Poland's terrain was well suited for mobile operations when the weather co-operated; the country had flat
plains, with long frontiers totalling almost . Poland's long border with Germany on the west and north, facing East Prussia, extended . It had been lengthened by another on the southern side in the aftermath of the 1938 Munich Agreement. The German incorporation of
Bohemia and Moravia and creation of the German puppet state of
Slovakia meant that Poland's southern flank was also exposed. Hitler demanded that Poland be conquered in six weeks, but German planners thought that it would require three months. They intended to exploit their long border fully with the great enveloping manoeuver of
Fall Weiss. German units were to invade Poland from three directions: • A main attack over the western Polish border, which was to be carried out by Army Group South, commanded by Colonel General
Gerd von Rundstedt, attacking from German
Silesia and from the
Moravian and Slovak border. General
Johannes Blaskowitz's 8th Army was to drive eastward against
Łódź. General
Wilhelm List's 14th Army was to push on toward
Kraków and to turn the Poles'
Carpathian flank. General
Walter von Reichenau's 10th Army, in the centre with Army Group South's armour, was to deliver the decisive blow with a northeastward thrust into the heart of Poland. • A second route of attack from northern
Prussia. Colonel General
Fedor von Bock commanded Army Group North, comprising General
Georg von Küchler's 3rd Army, which was to strike southward from East Prussia, and General
Günther von Kluge's 4th Army, which was to attack eastward across the base of the
Polish Corridor. • A tertiary attack by part of Army Group South's allied
Slovak units from Slovakia. • From within Poland, the German minority would assist by engaging in diversion and sabotage operations by
Volksdeutscher Selbstschutz units that had been prepared before the war. Polish forces were stretched thinly along the Polish-German border and lacked compact defence lines and good defence positions along disadvantageous terrain. That strategy also left
supply lines poorly protected. One-third of Poland's forces were massed in or near the Polish Corridor, making them vulnerable to a
double envelopment from East Prussia and the west. Another third was concentrated in the north-central part of the country, between the major cities of Łódź and Warsaw. The forward positioning of Polish forces vastly increased the difficulty of carrying out strategic maneuvres, compounded by inadequate mobility, as Polish units often lacked the ability to retreat from their defensive positions, as they were being overrun by more mobile German mechanized formations. However, in many places, German units crossed the Polish border even before that time. Around then, the Luftwaffe attacked a number of military and civilian targets,
including Wieluń, the first large-scale city bombing of the war. At 08:00, German troops, still without a formal declaration of war issued,
attacked near the Polish village of Mokra. The
Battle of the Border had begun. Later that day, the Germans attacked Poland's western, southern and northern borders, and German aircraft began raids on Polish cities. The main axis of attack led eastwards from Germany through the western Polish border. Supporting attacks came from East Prussia, in the north, and a joint German-Slovak tertiary attack by units (
Field Army "Bernolák") from the German-allied Slovak Republic, in the south. All three assaults converged on the Polish capital, Warsaw. France and Britain declared war on Germany on 3 September, but
failed to provide any meaningful support. The German-French border
saw only a few minor skirmishes, and most German forces, including 85% of armoured forces, were engaged in Poland. Despite some Polish successes in minor border battles, the German technical, operational and numerical superiority forced the Polish armies to retreat from the borders towards Warsaw and
Lwów. The
Luftwaffe gained
air superiority early in the campaign. By destroying communications, the
Luftwaffe increased the pace of the advance which overran Polish airstrips and early warning sites, causing logistical problems for the Poles. Many Polish Air Force units ran low on supplies, and 98 of their number withdrew into neutral Romania. Germany attacked from three directions on land. Günther von Kluge led 20 divisions that entered the Polish Corridor and met a second force heading to Warsaw from East Prussia. Gerd von Rundstedt's 35 divisions attacked southern Poland. By 3 September, when von Kluge in the north had reached the Vistula River, then some from the German border, and
Georg von Küchler was approaching the
Narew River,
Walther von Reichenau's armour was already beyond the
Warta river. Two days later, his left wing was well to the rear of Łódź and his right wing at the town of
Kielce. On 7 September, the defenders of Warsaw had fallen back to a line paralleling the Vistula River, where they rallied against German tank thrusts. The defensive line ran between
Płońsk and
Pułtusk, respectively north-west and north-east of Warsaw. The right wing of the Poles had been hammered back from
Ciechanów, about north-west of Pułtusk, and was pivoting on Płońsk. At one stage, the Poles were driven from Pułtusk, and the Germans threatened to turn the Polish flank and thrust on to the Vistula and Warsaw. Pułtusk, however, was regained in the face of withering German fire. Many German tanks were captured after a German attack had pierced the line, but the Polish defenders outflanked them. By 8 September, one of Reichenau's armoured corps, having advanced during the first week of the campaign, reached the outskirts of Warsaw. Light divisions on Reichenau's right were on the Vistula between Warsaw and the town of
Sandomierz by 9 September, and List, in the south, was on the
San River north and south of the town of
Przemyśl. At the same time, Guderian led his 3rd Army tanks across the Narew, attacking the line of the
Bug River that had already encircled Warsaw. All of the German armies made progress in fulfilling their parts of the plan. The Polish armies split up into uncoordinated fragments, some of which were retreating while others were launching disjointed attacks on the nearest German columns. During this invasion, Hitler's troops made extensive use of
Pervitin, a recently discovered methamphetamine, which enabled the constant movement of the troops, who no longer felt the need to sleep for several days. The drug would later also be used, this time officially distributed, in the invasions of France and the USSR. Polish forces abandoned the regions of
Pomerelia (the Polish Corridor),
Greater Poland and Polish Upper Silesia in the first week. The Polish plan for border defence was a dismal failure. The German advance, as a whole, was not slowed. On 10 September, the Polish commander-in-chief, Marshal Edward Rydz-Śmigły, ordered a general
retreat to the south-east, towards the Romanian Bridgehead. The largest battle during this campaign, the
Battle of Bzura, took place near the
Bzura River, west of Warsaw, and lasted from 9 to 19 September. The Polish armies
Poznań and
Pomorze, retreating from the border area of the Polish Corridor, attacked the flank of the advancing German 8th Army, but the counterattack failed despite initial success. After the defeat, Poland lost its ability to take the initiative and counterattack on a large scale. The German air power was instrumental during the battle. The offensive of the
Luftwaffe broke what remained of the Polish resistance in an "awesome demonstration of air power". Rydz-Śmigły ordered the Polish forces to retreat in the same direction, behind the Vistula and San Rivers, beginning the preparations for the defence of the Romanian Bridgehead area. It was agreed that the Soviets would relinquish its interest in the territories between the new border and Warsaw in exchange for inclusion of
Lithuania in the Soviet "zone of interest". By 17 September, the Polish defence had already been broken and the only hope was to retreat and reorganize along the Romanian Bridgehead. However, the plans were rendered obsolete nearly overnight when the over 800,000-strong Soviet
Red Army entered and created the Belarusian and
Ukrainian fronts after they had invaded the eastern regions of Poland, in violation of the
Riga Peace Treaty, the
Soviet–Polish Non-Aggression Pact, and other international treaties, both bilateral and multilateral. Soviet diplomacy had lied that they were "protecting the
Ukrainian and
Belarusian minorities of eastern Poland since the Polish government had abandoned the country and the Polish state ceased to exist". The Polish border defence forces in the east, known as the
Korpus Ochrony Pogranicza, had about 25 battalions. Rydz-Śmigły ordered them to fall back and not to engage the Soviets. From the first day of invasion, the German air force (the
Luftwaffe) attacked civilian targets and columns of refugees along the roads to terrorize the Polish people, disrupt communications and target Polish morale. The
Luftwaffe killed 6,000 to 7,000 Polish civilians during the
bombing of Warsaw. The German invasion saw atrocities committed against Polish men, women and children. The German forces (both
SS and the regular
Wehrmacht) murdered tens of thousands of Polish civilians (such as the
Leibstandarte SS Adolf Hitler was notorious throughout the campaign for burning villages and committing atrocities in numerous Polish towns, including massacres in
Błonie,
Złoczew,
Bolesławiec,
Torzeniec,
Goworowo,
Mława and
Włocławek). Polish women and girls were raped en masse by the German invaders and then executed. In addition, large numbers of Polish women were routinely captured to force them into prostitution in German military brothels. Nazi raids in many Polish cities captured young women and girls, who were then forced to work in the brothels frequented by German officers and soldiers. Girls as young as 15 years old, who were classified as "fit for agricultural work in Germany", were sexually exploited by German soldiers at their destination. Altogether, the civilian losses of Polish population amounted to about 100,000 or between 150,000 and 200,000, the large majority of which were due to German war operations and terror. In Warsaw alone, 15,000 to 25,000 civilians lost their lives. The deaths also included 12,136 Polish citizens of Polish and Jewish background killed in 615 known executions perpetrated by the German military, police and security forces before the close of the operations within the post-war borders of Poland. In the German-occupied territories, a mass
ethnic cleansing campaign called
Operation Tannenberg was started in the course of the hostilities by the Wehrmacht and the
Einsatzgruppen. Roughly 1,250 German civilians were also killed during the invasion. (Also, 2,000 died fighting Polish troops as members of ethnic German militia forces such as the
Volksdeutscher Selbstschutz, which was a
fifth column during the invasion.) The invasion of Poland marked the beginning of the Holocaust ("holocaust by bullets"), not only in its strict sense of the genocide of Jews, but also in its broader meaning of mass killings of various ethnic, political or social groups. == Aftermath ==