Preliminary Incidents
Hitler had given top priority to engineering an incident that would provoke the Poland into retaliation and thus justify German invasion. On 5 August 1939 the head of the SD (the Security Service of the SS), Reinhard Heydrich, entrusted the 28-year-old Alfred Naujoks with the task of creating just such an incident.
To set off the powder barrel, Heydrich outlined a complex plan for blowing up the German radio station at Gleiwitz (Gliwice). A team of six commandos were to be dressed up as Polish soldiers and seize the radio station, taking its occupants prisoner. Then, a specially picked announcer who could speak Polish was to make a provocative speech, boasting of Poland’s success in taking over the radio station. An engineer from Radio Berlin was to ensure that this was broadcast to the whole of Germany. Finally, a Jewish concentration camp inmate was to be dressed up as a Polish soldier, shot dead, and left in front of the radio station.
The attack on night of August 31 was successful, but the wireless expert was only able to broadcast on the local programme. That night there were two other incidents. At 4 a.m. operation ‘Agathe’ was launched against a customs house in Hochlinden and a forester’s house in Pitschau, by a group of German SS men disguised as drunken Polish pillagers.
Wehrmacht’s orders
The Wehrmacht was fully deployed for Fall Weiss by midnight of 31 August, and action was scheduled to begin on 4:45 AM. German forces were to encircle and destroy the Polish Army at the earliest possible moment, so that troops could then be transferred westwards to deal with the threat of a French invasion. Army Group North’s aim was to move into the Polish Corridor and cut off Gdynia from the rest of Poland. Once the Corridor was occupied, the XIX Motorized and Panzer Corps would move east and, together with the Third Army, mount a southwards movement against Warsaw. In the south, the Tenth Army was to smash through the Polish border defences and advance rapidly on Warsaw, while the Fourteenth Army would shield its southern flank from the Polish Army Kraków and send Panzer and motorized forces deep into Poland to meet up with troops from Army Group North on the axis of Deblin–Lublin– Chelm.
1 – 17 September: Danzig, Westerplatte and Coastal Regions
Old German battleship Schlesweig-Holstein opened the war at 4:45 hours by bombardment of the arsenal at Westerplatte, which was used as a transit base for war materials by the Polish Army. Concurrently with the bombardment, SS Heimwehr (Home Defence) Danzig Division supported by naval commandos and paramilitary units began operations to occupy Polish outposts in the city. While most targets were quickly occupied, the Polish Post Office and the arsenal at Westerplatte caused them considerable problems. All personnel at the Post Office were military reservists and the building had been considerably strenghtened in 1930., and so first two attacks by the armed police and SS Heimwer Danzig Division were easily beaten back. Post Office was taken in late afternoon after a flamethrower was used to smoke out the defenders, who were later charged with war crimes, brought before a war tribunal and shot.

Capture of Westerplatte Complex was necessary to enable destruction of Polish forces in Gdynia and on the Hel Peninsula. But Germans did not have accurate information on defences of the Westerplatte. Assumption was that bombardment by Schlesweig-Holstein had sufficiently reduced the defences of the complex to allow its capture by a naval commando force. In fact, the Germans faced a ring of fortified underground concrete bunkers and an elite force of 210 men under the command of Major Henryk Sucharski.
Unsurprisingly, the first German attack on 7:07 on 1 September was repulsed, as was the second attempt made twelve hours later. In these two attempts Germans had suffered 82 dead or wounded, to only four Polish casualties. The following day a battalion of sappers was sent by the Army Group North and Westerplatte was also bombarded by the Luftwaffe. This was followed up by heavy mortar bombardment. By the night of 5/6 September, the garrison was physically and mentally exhausted and had suffered a large number of wounded. Because of this and German successes on other fronts, Sucharski decided to surrender on 7 September. In a display of respect, Germans allowed Sucharski to wear his sword into captivity.
Once the German troops had occupied the Corridor, Polish air forces present as well as remaining naval forces that had not escaped to Britain – destroyer Wicher and a number of minesweepers, minelayers and torpedo boats – were destroyed by the Luftwaffe Ju-87 Stuka dive bombers. Wicher, minelayer Gryf, six minesweepers/minelayers and two gunboats were attacked by Stukas while on a minelaying mission off the Hel Peninsula. Gryf was heavily damaged and forced to return, but on 3 September Gryf, Wicher and shore-based artillery beat off German attack on Hel peninsula. Both ships were sunk in the early afternoon by yet another German air raid.
Hel Peninsula was defended by shore batteries and coastal defense forces numbering some 2 800 troops, while further 14 000 troops held the the defensive perimeter on the Oksywie Heights overlooking the Gulf of Danzig. These consisted of naval and artillery units as well as workers’ militias. Germans assembled 26 000 troops to eliminate them, mostly frontier or paramilitary troops, and further 12 000 troops were added following the fall of the Westerplatte.
Having secured domination of the skies over Poland by 6 September, Luftwaffe was able to employ small groups of hydroplanes, Stukas and Heinkels to bomb and machine gun Polish positions on the Hel Peninsula and Oksywie Heights several times a day. Two days later, Polish resistence on Oksywie Heights was broken, while the Hel Peninsula held out until 1 October.
1 – 6 September: Rout of the Polish Air Force
The German Air Force in the Eastern Germany consisted of two air fleets. In the north was Luftflotte 1, under General Albert Kesserling. It numbered 1 105 aircraft, of which 526 bombers. Luftflotte 4 in the south was commanded by General Alexander Lohr. This fleet numbered 729 aircraft of which 303 were bombers. To oppose this force, Poland had 397 combat aircraft, of which 154 were bombers (36 medium and 118 light).
Senior officers of the Luftwaffe were following Italian air strategist Giulio Douhet, who insisted that “a decision in the air must precede decision on the ground”. Thus the Luftwaffe was structured to destroy its enemies’ air forces as quickly as possible – and preferably before they could even take off. After achieving mastery in the air, Luftwaffe would shift to supporting troops on the ground through close air support and interdiction missions.
But the events of the campaign precluded this, and in reality Luftflotten 1 and 4 had to pursue these objectives concurrently. From the start, Luftwaffe worked in close cooperation with troops on the ground.
German plans to launch a massive attack against the Polish Air Force on 1 September were upset by low clouds and fog, and thus degenerated into a series of individual actions. In the north, Luftflotte 1 only managed to launch seven attacks, five of which were against the air fields. In the south, more favorable weather conditions allowed attacks to be launched on time. Most were against air fields, but a significant number of attacks was aimed against the ground forces. Attacks against ground targets were very effective and led to disintegration of entire Polish units, but attacks against air fields failed to achieve their objectives as Poles had moved their aircraft to emergency air strips. Only training aircraft were destroyed.
While Polish Air Force was seriously outnumbered and flying outdated machines – especially fighters – the Pursuit Brigade managed to inflict serious losses on the German forces over Warsaw thanks to effective early warning system. Two attacks by hundreds of German bombers were beaten off by some fifty fighters of the Pursuit Brigade, with German bomber formations failing to inflict any damage on their targets: armaments factories and bridges over Vistula. By the end, the Pursuit Brigade had lost ten fighters with maybe four times as many damaged, and had achieved twelve confirmed air victories. Polish pilots found that German pilots were their equals, but German bombers were very innacurate – with notable exception of the veterans of the Condor Squadron that had served in Spain, which had managed terrifying levels of accuracy.

But Polish Air Force was losing strength fast, to the point that the Pursuit Brigade was being ordered to carry out reconnaissance sweeps elsewhere. In the evening of 6 September the Pursuit Brigade – now down to 16 fighters out of 54 – was ordered to evacuate Warsaw for the Lublin area behind Vistula. Meanwhile, the bomber force was being completely useless, partly due to Rydz-Smigly’s indecisiveness. Until 3 September the British and the French urged him not to use bombers against targets within Germany, lest he provoke Hitler even more. Karas light bombers attacked enemy armor on 2 September, and also regularly loaded bombs to attack targets of opportunity. On 3 September Karas II/2 squadron attacked German armored forces in the Radomsko region, NE of Czestochowa. Between 4 and 6 September both light Karas and heavy Los bombers repeatedly attacked German forces in the Piotrkow sector between the Army Lodz and Army Krakow, as well as further west in Wielun and north in the Pultusk area. Von Höpner’s XVI Campaign Chronicle 74 Armoured Corps in the Piotrków sector reported on 4 September that Polish air strikes had knocked out some 28 per cent of the 4th Armoured Division.
Elsewhere, Polish Air Force used flights, pairs or even single fighters operating from hastily constructed ambush fields to oppose the Luftwaffe. Dispersed basing allowed the Polish fighters to survive in the face of German air superiority, but they were too few to have noticeable impact on Luftwaffe’s operations. PAF had no choice but to follow the Army in its retreat and attempts to regroup. Fighter planes attached to Army Krakow were pulled back first to Deblin and then to Lublin.
Luftwaffe dive bombers were having devastating impact on the mobility of Polish ground forces. They destroyed roads, railways, as well as bridges across the rivers of Narew, Vistula and Bug. Temporary bridges were destroyed almost immediately as they were begun, and bombing of railways stations forced Polish forces to completely abandon rail transport in many areas. Luftwaffe also intercepted underway rails. The end result of these activities was a complete disorganization of Polish military movements in the first few days. Dive bombers also perfromed excellently in strategic bombing role – better, in fact, than dedicated strategic bombers. Thanks to dive bomber attacks, the Polish air industry was completely out of action by 5 September.
By the second week of the war, the Luftwaffe completely dominated air over Poland. Its fighters and dive bombers harried refugees on the roads, interdicted rail traffic and prevented troop concentration. Constant psychological pressure also caused numerous cases of psychical breakdown.
1 – 7 September: The Land War
While everything was happening, German Army Groups North and South had crossed the frontiers and were probing Polish defences. Fourth Army was to eliminate the Corridor and link up with the Third Army coming from East Prussia. Poles managed to blow up the crucial Tczew bridge, which was a vital link carrying road and rail traffic from Germany and Danzig across Vistula. Germans managed to sieze Tczew on 1 September and crossed into the Corridor. As Polish Army Pomorze was essentially a trigger force and not intended for a stand-up fight, it began withdrawing southwards to a more tenable position. Poles assumed that Tuchola Forest would act as a barrier to German panzer units, and were surprised when a Panzer division, two motorized and three infantry divisions attacked straight through the forest. Poles managed to hold the German infantry, but German 3rd Panzer division had crossed River Brda unnoticed and was about to threaten the Polish rear.
It was here that an incident occured which would be later used by German propaganda to depict Polish army as hopelessly outdated. Having spent the entire day fighting against the German 20th Motorized Infantry Division, Polish 18th Regiment of Pomeranian Ulans (lancers) were refused request to retreat to a more favorable position. Colonel Kazimierz Mastelarz decided to remount his two depleted line squadrons and attack German infantry from the rear. The attack was successful, but Polish cavalry was surprised by a squadron of German armored cars which killed some twenty men, including the commander, before Poles could take cover. Italian journalists who visited the battlefield day later were informed that Polish cavalry had charged tanks, when in reality cavalry units had anti-tank guns for such purpose.
These successes however were only temporary. By 2nd September Polish forces in the Corridor were being surrounded, with 3rd Panzer Division being near Poledno, almost exactly to the rear of Polish positions. 32nd German Infantry Division also slipped through. Only Polish 27nd Division, 9th Infantry Division and remnants of the Pomorska Cavalry Brigade managed to escape the encirclement. On 3rd September the Polish forces were ordered to withdraw beyond Vistula, having lost 10 000 men.
In Bydgoszcz, native Germans (Volksdeutche) attempted to sieze control of the city early on 3rd September. In this they were aided by German agents who had come across the border as refugees. The plan was to sieze control of the town by 11 o’clock when German panzers were due to arrive, but tanks only arrived 24 hours later. The District Officer and his colleagues managed to form resistance, collecting some 200 men armed with rifles. By 6 PM, the attempted takeover was defeated, with some 1 000 rebels having been shot or executed, but approach of German tanks forced evacuation of the city nevertheless. Last Polish troops left on the night of 4/5 September, leaving defense of the city in the hands of the civilian militia of some 2 200 workers and students. Germans, having received fire upon entering the city, responded by razing to the ground every building from which the fire had come. By the afternoon of 5 September the city had surrendered, and Germans proceeded to execute any Poles who had shot ethnic Germans. These were identified by the local Volksdeutche and immediately shot. Sniping against German troops continued however, and on 9 September Germans shot 400 Polish hostages in the town square.
As German Fourth Army was advancing through the Corridor to link up with the Third Army, the Third Army launched on 1 September a two-pronged attack on the Polish defences facing eastern Prussia which were manned by Army Modlin. Strong Mlawa stronghold held up Germans until 3 September when Kempf Panzer Division outflanked it through the gap opening up between two Polish infantry divisions and the Mazowiecka Cavalry Brigade. By the late afternoon of the 4 September the entirety of Army Modlin was withdrawing to Vistula, but heavy losses had rendered it incapable of actually defending the river. German Luftwaffe had played significant part in eliminating Polish fortifications and in disordering retreating forces. By 5 September what was left of Army Modlin had been pushed back to Modlin itself. German Kempf Division routed the Polish 41st (Reserve) Infantry Division at Ró²an and managed to cross the River Narew, endangering Warsaw from the North.

No large scale fighting was occuring to the south along the salient held by Army Poznan. Combat there consisted of small-scale clashes and diversionary attacks for the first three days of the war. 9th Ulan Regiment there was first ordered to relieve a battalion of the National Defense Force 9 miles NW of Poznan, and two days later was ordered to retire eastwards to Gniezno and blow up the bridges over the Warta. Then they were ordered to retire to Sepolno and cover the regrouping of Armies Poznan and Pomorze.
German advance towards Lodz on 5th September caused General Kutrezba to request of the High Command in Warsaw to use the southern elements of his Army Pomorze together with Army Poznan to attack the German Eighth Army on its northern flank. This was dismissed as premature, but would inspire Polish action on Bzura one week later.
The main thrust of the German offensive was in the South-West and aimed at the joint of Armies Krakow and Lodz, and thus had the greatest concentration of troops and armor. Army Group South was opposed by the Army Krakow, then the largest Polish army, and Army Lodz. Despite being forced to defend the Upper Silesian industrial regions it managed to hold the Germans back for several days, but in the end German armor managed to exploit gaps in the Polish lines and outflank the defenders.
Germans launched a series of attacks all along this front at dawn of 1st of September. The German Eighth and Tenth Armies launched a series of infantry attacks through the forested area along the frontier controlled by the Army Lodz. Main Polish defense line was about 20 miles inside Poland, with a series of largely successful delaying actions being fought in the area in front of it.
Germans however achieved significant successes against the Army Krakow in the south, where the 1st Panzer Division opened a gap between the Wolynska Cavalry Brigade defending Mokra and the Polish 7th Division to the south. Fortified city of Katowice was a more difficult target, but even there panic was spreading and the German Volksdeutsche – paramilitary of ethnic Germans in the city – was ready to assist the Wehrmacht advance by siezing key buildings in the city. Several attempts were in fact made, but suppressed.
On 3 September the 5th Panzer Division managed to break through the Polish defences near Oswiecim (Auschwitz) and the Polish defence at Katowice was broken. In Eastern Silesia, German advance was slowed down considerably by the Polish militia and the civilians who continued to harass the rear echelons, using hedgerows, underbrushes and sniper fire to fight isolated actions which heavily disordered the advance battalions. To combat the Polish guerillas, German commanders deployed Waffen SS and Einsatz Commando units. West of Lodz, order came on 2 September to burn down several villages.
Germans initially made little progress against the Army Karpaty due to difficult terrain. For two days they were held along the Dunajec–Nida line by the 10th Mechanized Brigade, KOP troops and a regiment from the 6th Infantry Division. This prevented the Germans from encircling Krakow and driving a wedge between Armies Karpaty and Krakow.
During the next three days, Runstedt’s Army Group South attempted to push through the juncture of the Polish Armies Lodz and Krakow. City of Wielun at the main defensive position of Army Lodz was captured on 2 September, and Polish forces in retreat failed to destroy the last bridge over Warta which was captured by German panzers. Other bridges were also quickly repaired, so to counter this threat, Poland had to throw the Reserve Army Prusy into combat despite it not having completed the mobilization. Thanks to reconnaissance by the 23rd Grodno Ulan Regiment, Polish bombers managed to attack a column of German motorized infantry. There were also some local successes, including by cavalry.
Planned counterattack by Army Prusy was countered when the German 1st Panzer Division moved against Piotrkow. Initial advance was repulsed with Germans losing 17 tanks and 16 other armored vehicles while destroying only two Polish tanks. In the afternoon however the 1st Panzer Division managed to ouflank Piotrkow, opening the road to Warsaw. By the evening of the 5th December, Army Lodz was cut off from Army Prusy and Army Krakow, and threatened with encirclement. Due to this, Marshal Rydz-Smigly ordered the Armies Krakow, Prusy, Poznan and Lodz to pull back to defensive positions east of Vistula. As Army Krakow’s position continued to deteriorate, it was ordered to withdraw over the river Dunajec on 6th of December.
Britain and France Declare War

Three days after the invasion, Britain and France finally declared war against Germany. News caused joy in Poland and alarm in Germany, but Hitler proved correct in his belief that the declaration was nothing but a meaningless gesture. Britain and France were ready to fight to the last Pole, and even there they underperformed, failing to provide any material help. Both Polish ambassadors in Britain and British ambassadors in Poland maintained a constant refrain to London that arrival of war materiel – especially fighter aircraft – would provide a moral and psychological effect far in excess of their physical impact. This was significant as, should Poland prove to be able to maintain the new, shortened defensive line, Germans will have had major supply difficulties and it was to be expected that Poland will have been able to maintain the eastern front should western Allies react promptly react and force Germany to shift forces westward.
However, because Poland’s armament factories had been heavily bombed, there was urgent demand for both weapons and ammunition – machine guns, ammunition for them and for AA guns, gas masks and lorries. Western allies were unable to supply any of these due to their own requirements.
It was planes Poland needed the most, and while some were provided, it was too little and too late – three ships containing 35 Fairey Battles, 14 Hurricanes and 1 Spitfire, gas masks and 500 000 Hotchkins machine guns were dispatched by the British Government. Request to bomb German industry had been rejected as the French had requested the British to withhold action against German industrial centres, originally planned for 8 September. Why that was done is unknown. Instead of bombs, Royal Air Force opted to dropping leaflets over Germany, beginning in the night of 3 September when ten aircraft flew over Ruhr dropping 13 tons of leaflets. Daladier, the French Prime Minister, attempted to send 50 planes from Dunkirk and Maresilles, but the pre-war plans to send French units to directly assist the Polish Army had to be shelved after Czechoslovakia had been occupied by the Germany. French explained to Poles also that all fighters were required to protect their own forces from the Luftwaffe, but these forces did nothing of note, crossing the German forces in only three points before allowing themselves to be stopped by the objectively pathetically weak defences and forces left along the Siegfried Line. In fact, no major clashes with German troops had occured before the French had stopped their advance.
8-17 September: Battle of the Bzura
On 6 September the British Military Mission informed London that “the two most dangerous [German] attacks at present are those of the motorized groups from Silesia and the forces moving southwards on Warsaw from East Prussia. Should these two arms of the pincers succeed in effecting a junction, a large portion of the old Polish Army might be surrounded”. [Source: NA WO 193/763.]
Polish Lodz and Pomorze armies were retreating to the main defensive line at Vistula, but German troops attacking Polish forces around Tomaszow Mazowiecki were nearer to this defensive barrier than they themselves were, and threatened to encircle them. In an attempt to avert this, Marshal Rydz-Smigly ordered the formation of a new force, Army Lublin, from the remaining reserve units. Threat by German 4th Panzer Division approaching Warsaw forced the Marshal to move the High Command from Warsaw to Brzesc. This in turn caused the High Command to lose contact with the Polish armies just as the main defensive line on Vistula was being prepared. German 5th Panzer Division moved through the mountainous area to at the same day threaten the rear of Army Krakow, and two German Light Infantry divisions crossed Vistula and siezed Tarnow. Army Malopolska withdrew from the Nida-Dujanec line on 6 September, making Army Krakow’s position untenable, and Armies Lodz, Prusy and Pomorze were also in the full retreat. Only Army Poznan managed to retreat in good order.
German fast eastward advance however opened them to General Kutrzeba’s plan to strike at the German northern wing with three infantry divisions and two cavalry brigades. But Polish High Command wanted Armies Pomorze and Poznan to regroup east of the Vistula to help defend Warsaw, a move which Kutrzeba knew will have opened the retreating armies to attack by German air and motorized units. While he decided to obey the order on 6 September, he still looked for an opportunity for a flank attack. After two days’ march – during which his troops destroyed everything Germans could use – he decided that further march is useless and that better option is to stay and fight. He correctly believed that the Germans had underestimated the size of his force as his army moved primarily at night, and aimed to exploit this.
However, as Rydz-Smigly was in the process of moving his headquarters, General Kutrzeba was only able to obtain approval for his plan on the afternoon of 8 September. The main aims of the offensive were to disrupt the Wehrmacht’s advance on Warsaw and sieze Leczyca and Piatek. The Chief of Staff had hoped to coordinate the attack with Armies Lodz, Pomorze and Polish forces to the west of Warsaw, but Army Pomorze was too far, and Army Lodz was falling apart due to lack of food and roads blocked by the refugees. Due to lack of motorization, armies had to march and thus infantry were tired when time for major action came.
This happened on 9 September, when Polish forces attacked in the direction of Kros. Despite one of Polish units attacking prematurely, the scale of the attack still took Germans off guard. In Leczyca, German artillery ran out of the ammunition and then the infantry it was supporting got encircled. After several attacks Piatek was taken. On the following day, German 46th and 30th Infantry Divisions were retreating in complete disorder, and the X Army Corps HQ was informed that the situation was “deadly serious”. Some of the German troops were “beginning to be resigned to defeat”, a situation made worse by the Polish cavalry activity in the rear. Polish cavalry was destroying isolated German units and raiding supplies.

The OKW was able to quickly respond to the worsening situation. The remaining units of the German Eighth Army were moved northwards, and decision was made to encircle the Army Poznan and destroy the whole of the Kutrzeba’s forces. Reserve divisions of the 8th Army as well as the remnants of the routed 30th and 26th Infantry Divisions would move in from the west. 3rd Light as well as 1st and 4th Panzer Divisions, in action near Warsaw, were moved to the eastern flank.
But even before these measures could be executed, Polish advance was already running into problems. Despite promises, Kutrzeba received no air support, and his artillery support was very limited. Wide open flood plain of the Bzura helped German defense and was ideal for movement of the panzers. While Polish infantry usually won in hand-to-hand combat, it lacked crucial artillery support and so any advance was very costly. By 11th September Germans were mounting successful local counterattacks, and by 12th September Polish forces in the Bzura region were outnumbered 1,3 to 1 in infantry, 2,4 to 1 in artillery and 4 to 1 in armor. Kutrzeba thus had to redirect his attacks from south to the east, giving Wehrmacht time to bring in valuable reinforcements. By 16th of September Kutzreba’s forces were surrounded, and only the remnants of the cavalry as well as 15th and 25th Infantry Divisions managed to break out and seek shelter in the Kampinow forest.
Germans managed to surround the forest with tanks and infantry, and while Polish cavalry under Rudnicki managed to escape and join the battle for Warsaw, troops left behind faced Germans alone. By 18 September the organized resistance had collapsed, and by 21 September Armies Poznan and Pomorze had ceased to exist. Germans had taken over 100 000 Prisoners of War.
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