Invasion. 1 September 1939 at 5:45 on the Polish-German border. The picture originates from German sources. The German soldiers obviously pose for the photograph: they break the barrier from the Polish side of the border as is indicated by the Polish national emblem.

Explosions of bombs and rattle of anti-aircraft machine guns early in the morning 1 September 1939 were taken by Varsovians for sounds of military drills. The war was expected day after day. But nobody expected that a civilized European nation would start it without a formal declaration, that it would become a bandit assault.

The Polish defence plan can be compared to a curtain hung over a burning stack. The German invasion had to be countered by the grouping of several Polish armies deployed alongside frontiers. East Prussian borders were covered by the Independent Operation Group Narew and Army Modlin; Pomerania had to be defended by the Army Pomorze; farther to the south were deployed Armies Poznań and Łódź; the strongest of Polish armies, Army Kraków was assigned to defence of Silesia and Carpathian passes together with the weakest one, Army Karpaty. Furthermore in central Poland, in the quadrangle Skierniewice - Tomaszow - Kielce - Radom had been formed the reserve Army Prusy.

An obvious weakness of the Polish grouping was its slenderness and dispersion of divisions along the very long border, which caused the spread of their operational stripes beyond acceptable limits. Of course the authors of the defence plan realised the nature of pending contest. They knew that it would be a manoeuvre campaign, relentless advance of mechanized troops and defence flexible by necessity. So they envisaged retreat operations. The Army Kraków had to become an axis, along which other units had to withdraw beyond Vistula. But this plan had a major disadvantage: slow, limited in their manoeuvre abilities to infantrymen legs, Polish armies were shifted too far westward and exposed to a rapid advance of enemy mechanized troops. There was also wasted operational potential of the only Polish rapid force, namely cavalry. The Poles had 38 cavalry regiments equipped with machine guns and artillery, and having a high morale strengthened by the society's sympathy. Properly used and unbound to roads they could quickly move and surprise enemies. Perhaps they even could challenge German advanced detachments to pierce shallow infantry groupings. However they became dispersed among Polish armies and they had no chance to wage a single fight of a strategic significance.

Polish mobilization plans foresaw calling to arms 30 field infantry divisions, 9 reserve infantry divisions, 11 cavalry and 2 armoured brigades, altogether 52 big units. They had to number 1,050,000 men in the army, 150,000 in reserve and 300,000 in the popular militia; altogether one and half of million men at arms. The country's human resources could even provide the army with three or more million recruits but there were no uniforms, no equipment, no weapon, no money. So military institutions sent many volunteers back to their homes. It may be accepted that Polish forces numbered about 1,100,000 men including rear units, many of which after all soon became exposed to military activities.

German forces numbered about 1,600,000 men. As a whole the German army was not ready yet. But the best units were pulled out and thrown against Poland. According to a French historian and military analyst, Alphonse Goutard, only the core of the German army had a military value. These forces were wholesale sent to Poland, which Adolf Hitler desired to destroy as soon as possible. No substantial reserves were left on the French frontier. Almost all the infantry divisions (44 out of 52), all the armoured, light and motorized divisions, and the whole Luftwaffe rushed to the east.

But superiority in numbers does not mean yet superiority in quality. And this was especially true with the German technical superiority.

In the Polish campaign a German armoured division had 400 tanks, including 48 heavy and 84 medium ones. There were seven armoured divisions. Each of four light divisions had 200 tanks and dozens of armoured vehicles. Each of four motorized divisions carried soldiers in lorries right to the very front line. Independent tank and armoured carrier units accompanied infantry divisions. Altogether the Germans used against Poland about 3,000 tanks. They were supported by 5,000 guns and 1,600 aircraft. Poland could oppose them with about 900 tanks and armoured cars, 2,000 guns, and about 400 aircraft, mostly obsolete ones. Besides, the Polish Air Forces possessed virtually no reserve planes. With heavy losses of planes in fights on the first days of the war, they were eliminated from further hostilities as a considerable factor.

The forces designated against Poland were divided into two Army Groups. First of them, called North and commanded by Gen. Fedor von Bock, had to seek the seizure of the Pomeranian "corridor" and then to support the southern wing of German armies in order to close Polish forces in a gigantic pocket west to Vistula. The group was comprised of the 3rd Army (Gen. Georg von Küchler) deployed in East Prussia and the 4th Army (Gen. Günther von Kluge) deployed in Pomerania. Far bigger and stronger Army Group South (Gen. Gerd von Rundstedt) had to determine the lots of the campaign. It was made of the 8th Army (Gen. Johannes von Blaskowitz), which had to strike against Posnania securing the left wing of advancing main forces, the 10th Army (Gen. Walther von Reichenau), which had to carry out the main effort from Silesia to Warsaw, and the 14th Army (Gen. Wilhelm List), which had to advance from Silesia to Cracow and Lwow. The commander-in-chief of the forces engaged against Poland was Field Marshal Walther von Brauchitsch, who since the beginning of 1938 was the supreme commander of the German land forces and commanded German forces during occupation of Austria and Czechoslovakia.

Land forces' activities were supported by two Air Fleets: the 1st, deployed in East Prussia and supporting the Army Group North, and the 4th, which supported the Army Group South from airfields in Silesia and Berlin.

The Germans also had engaged against the Polish coast a grouping comprised of a battleship, 9 destroyers, 13 minesweepers, and a pack of smaller boats and vessels. The Poles, after having sent three most valuable destroyers to the Atlantic, had 5 submarines, 1 destroyer, 1 minesweeper, and some smaller torpedo and gunboats. Moreover the Polish Navy was exposed to attacks of the German air forces, which possessed absolute ease in the air. In these circumstances the defence of the Polish coast was an enterprise purely honourable.

After all since the very first hours of the war it became clear that the Germans did not intend to observe any laws or habits of war, which are accepted among civilized nations. German aircraft used to attack both railways and shepherds in meadows, defence installations and defenceless hamlets, military columns hastening to the front and crowds of civilians fleeing the hostilities. Apparently the goal was not just to conquer Polish armed forces on battlefields, but to terrorize and destroy the entire nation, what after all was in accordance to the Hitler's directive:

Annihilation of Poland in foreground. Goal is elimination of the vital forces, not the attainment of a specific line. Even if war breaks out in the West, the destruction of Poland remains the priority. A quick decision in view of the season. I shall provide the propaganda pretext for launching the war, no matter whether it is credible. The victor is not asked afterwards whether or not he has told the truth. What matters in beginning and waging the war is not righteousness, but victory. Close heart to pity. Proceed brutally. Eighty million people must obtain what they have a right to. Their existence must be made secure. (...) The stronger is in the right. Supreme hardness. [Halder F. (1988).]

The defence delivered by the Poles was very hard and it brought to the Germans a lot of unpleasant surprises. But the great battle on Polish frontiers inevitably showed enemy's supremacy. In some sectors the Germans seized initiative at once, and by the third day of the war tiny infantry positions were pierced elsewhere. In Pomerania got annihilated in Tuchola Forest the northern wing of the Army Pomorze. It was there, in the battle of Krojanty, that German armoured columns virtually annihilated Polish cavalry troops that attempted to challenge them. This was instantly exploited by propaganda: German - as an example of Polish stupidity, and Polish - as an example of gallantry and devotion. In result of these activities the Germans opened the road to East Prussia and cut out the Polish coast.

The situation on the southern wing of Polish armies was even more dramatic. Yet on 1 September, at 9:00, the Germans seized Rybnik where two battalions of Polish infantry tried to halt a German armoured division. Near Czestochowa German armoured divisions hastening to Warsaw annihilated a Polish infantry division and thus created a 100-kilometres wide empty gap between armies Kraków and Łódź. Any efforts to plug that gap proved futile. Polish troops reinforced from east had been destroyed by Luftwaffe before they managed to reach the front line.

But the most important thing on those days was declaration of war by Western allies. It was clear to me, shrieked Hitler to his generals on 22 August, that a conflict with Poland had to come sooner or later. I had already made this decision in the spring, but I thought that I would first turn against the West in a few years, and only after that against the East. (...) It became clear to me, that in the event of a conflict with the West, Poland would attack us. [Bullock A. (1991).] But it was not equally clear, even on 1 September, that the West would strike against Germany in case of German invasion of Poland. Reluctantly Great Britain delivered an ultimatum and found herself in war with Germany on 3 September. Several hours later also France declared war on Germany. The British ultimatum had shaken the hitlerite summit. Former German foreign office's interpreter, Dr. Paul Schmidt, who had presented it to Hitler's chancellery, saw everywhere grave faces:

When I entered the room Hitler was sitting at his desk and Ribbentrop stood by the window. (...) I stopped at some distance from Hitler's desk and then slowly translated the British ultimatum. When I finished there was complete silence.

Hitler sat immobile gazing before him. (...) After an interval which seemed an age, he turned to Ribbentrop, who had remained standing by the window. What now? asked Hitler with a savage look, as though implying that his Foreign Minister had misled him about England's probable reaction.

Ribbentrop answered quietly: I assume, that the French will hand in a similar ultimatum within an hour. [Schmidt P. (1951).]

Even usually ebullient minister for propaganda, Josef Göbbels, stood in a corner downcast and self-absorbent. Hermann Göring, the minister of air forces, concluded: if we lose this war, then God have mercy on us! This episode illustrates how much the Germans believed in possibility to isolate Poland and to dispose her with absolute passivity of the rest of Europe.

Western powers' declaration of war was cheered in Warsaw, but it did not help Polish armies being in complete rout. On 4 September they left Grudziadz and Bydgoszcz. After the fall of Upper Silesia, it came the turn of Cracow, left on 5 September evening. On 6 September during a raid of German aircraft, the commander of the Army Łódź, Gen. Juliusz Rómmel, made a retreat from his headquarter. He retreated however somewhat too far, as far as to Warsaw, and lost contact with his troops since then led by Gen. Wiktor Thommée. Meanwhile advanced columns of the German 10th Army were already fighting unprepared units of Polish reserve grouping. Preserving the main axis of advance via Piotrkow to Warsaw, the German command had though unfolded several armoured and mechanized columns fanned out towards mainstream Vistula. In this situation the Polish Supreme Command ordered a retreat beyond Vistula and Dunajec. At night from 6 to 7 September Polish military and state authorities left Warsaw and headed to the south, towards the Romanian border. After them rushed other institutions and diplomatic missions. Refugees, soldiers and deserters from the battered troops, and recruits seeking their units crowded eastbound roads. Simultaneously intensified German "fifth column" recruited among Poland's German and Ukrainian inhabitants. In these conditions the control over Polish defence had become virtually impossible.

On 7 September capitulated Westerplatte, a Polish outpost in Danzig, which was supposed to deliver only a 24-hours defence. Nevertheless two hundred soldiers armed with rifles and one obsolete gun within a week opposed 2,200 men supported by 30 guns and air forces. The battleship Schleswig-Holstein was firing at Westerplatte at blank point. In recognition of Poles' gallantry the Germans granted the Polish commander the right to carry his sabre in captivity. But it was a rare gesture of fairness towards the conquered. Hitlerite bands used to massacre prisoners and civilians as they did it with defenders of the Danzig Polish post office or railway officers in Tczew.

Free City of Danzig was seized on the first day of the war. Polish coastal and naval forces were helpless in face of German air and naval might. On the third day of war the Polish Navy lost its two biggest ships; others were incessantly chased by German aircraft. Land positions were under permanent artillery fire. It was a fortunate decision to send three Polish destroyers to the Atlantic. In the Gulf of Danzig they would cost the Germans some ammunition. In England they formed the nucleus of the Polish Navy fighting efficiently alongside the Royal Navy. Nevertheless Polish troops, cut out from the rest of the country, were fiercely defending Gdynia, Wejherowo and Hel and were expecting help. This however was not to happen.

On 8 September German units reached Warsaw, seized the city's airfield and attacked its westmost districts. Although promptly dislodged, they started a regular siege and artillery barrage. Moreover, the enemy had crossed Narew and menaced Warsaw from the east.

Meanwhile in the headquarter of the Army Poznań was conceived a bold plan of strategic counter-advance, which had to be done by the core of the Army's troops towards Radom. The Army Poznań found itself in between two main axes of German offensive and was not engaged in hostilities. Moreover, it had absorbed units from the destroyed Army Pomorze and expected co-operation of the Army Łódź. They had to strike against the left wing of advanced German divisions, then pierce from the west to south-east and restore defences beyond Vistula. But practical realization of the plan proved impossible.

On 9 September morning started regular fights for Warsaw. The Germans struck with 300 tanks alongside main city's communication corridors. Although armed civilians reinforced regular troops, their positions became pierced and street fights started. The Army Łódź, which did not manage to break through the German positions, got destroyed and its scattered units were retreating beyond Vistula. In the north the Germans, after scattering of the right wing of Polish armies and crossing of river Bug, had advanced to Minsk Mazowiecki and Siedlce and were near to close the encirclement ring around Warsaw. On mainstream Vistula the Germans had won the race to the bridges across the river and cut Polish units from passages. Heavy fights for passages started, which lasted several days and are known as the battle of Radom. And in the south German divisions reached San. Even the weather was in favour of invaders. Extraordinarily high temperatures had literally drunk the water from rivers and exposed fords unknown for decades. Neither San, nor Bug nor even Vistula made any serious natural obstacles.

But due to lack of proper communication the commander of the Army Poznań, General Tadeusz Kutrzeba, was unaware of the existing situation when he ordered his forces to strike from Bzura River to the south. The advance literally annihilated the leftmost German 30th Infantry Division. The Poles instantly recaptured Leczyca and Piatek, and challenged German positions in Strykow, as well as in suburbs of occupied Lodz. The advance menaced German infantry divisions moving behind armoured ones. Their positions were stretched along the line Skierniewice - Lowicz - Sochaczew - Blonie. While German air forces were engaged elsewhere, six Polish infantry divisions and two cavalry brigades managed to fight efficiently seven German infantry divisions, but the German command could manoeuvre its forces, while Gen. Kutrzeba had not such possibility. He could count neither on reserves, nor rapid armoured troops, nor air forces, nor even communication with the Supreme Command, which after all did not control the war effort any more. The Germans instantly sent to the menaced sector two armoured divisions, three light ones and a motorized one. Finally they struck from the air with several hundred planes detached from both air fleets. Gen. Kutrzeba had understood impossibility to recapture Lodz and decided to turn to Kutno and to seek a way to Warsaw. "The biggest and the bloodiest battle in the hitherto military history", as it was described by the Germans themselves, extinguished on 20 September. Some forces with Gen. Kutrzeba had pierced through Kampinos Forest to Warsaw and strengthened its defence. The rest, with wounded Gen. Władysław Bortnowski surrendered. Three other generals fell in fights.

In other sectors the defence was also in the state of complete rout. Since 12 September German rapid units operated east to Vistula and challenged Lublin. The same day troops advanced from Slovakia besieged Lwow, others reached Przemysl and Drohobycz. In Stryj Ukrainian nationalists scattered Polish authorities and launched slaughter of Polish inhabitants.

And how, in the mid-September, did look the help of Poland's allies? It was not until 4 September that in Paris was signed the Polish-French political protocol, which had to replace the decayed alliance of 1921. The new alliance was finally concluded on 9 September. The Poles appealed to engage the French army. On 10 September the French Supreme Commander, Gen. Maurice Gamelin, sent the Polish ambassador a note, which stated:

More than half of our active divisions on the northeast front is engaged in combat. Beyond our frontier the Germans are opposing with a vigourous resistance. (...) Air action from the beginning has been under way in liaison with ground operations. We know we are holding down before us a considerable part of the German air force. I have thus gone beyond my promise to take the offensive with the bulk of my forces by the fifteenth day after mobilization. It has been impossible for me to do more. [Gamelin M. (1946).]

Unfortunately Gamelin had simply lied in his note. What did the "offensive with bulk forces" look like? Goutard gives an account:

The offensive was carried out not by 35 divisions but by 9 divisions, of the Fourth and Fifth Armies. The Third Army, which occupied the Wendt Forest seems to have employed 2 divisions. (...) There was no action in the air except for a few reconnaissance missions. (...) There was no "vigourous resistance" on the part of the Germans. After almost bloodless skirmishes they drew back to the Siegfried Line. (...) Not a single German division or tank or plane was diverted from Poland to reinforce the West. [Goutard A. (1956).]

When Gamelin had completed this grotesque enterprise he condescended to call an offensive, he stated that due to development of situation in Poland nothing could help this country. But Alfred Jodl, one of nazi war criminals hung in Nuremberg, and during the war Colonel-General, one of the most trusted Hitler's advisers, in 1945 testified before the Allied tribunal the contrary:

If we did not collapse in 1939, that was only because the approximately 110 French and English divisions in the West, which during the campaign in Poland were facing 25 German divisions, remained completely inactive. [Fest J. C. (2002).]

Let us add, that only few of German divisions were regarded as combat units. Another high-ranking German militaryman, former chief of staff at the Oberkommando West, namely the Supreme Command West, Gen. Siegfried Westphal admitted, that a resolute allied offensive in west in September 1939 would cause the collapse of the hitlerite régime by the end of the year. The complete passivity of powers ensured a complete ease to the barbarians, in comparison to whom the medieval Mongols look like gentlemen. For that mistake the mankind had to pay a terrible price.

At the final stage of the battle of Bzura one tried to gather the rests of the Polish army in three basic groupings: the Army Warszawa, which was defending Warsaw and Modlin, the Gen. Stefan Biernacki-Dąb's army operating in the north, and the Army Małopolska, operating in the south under command of Gen. Kazimierz Sosnkowski, hitherto disfavoured by the Polish régime. All the organizational shuffles turned already futile though. Biernacki-Dąb simply abandoned his troops telling that he was not going to expose his soldier glory in such a brothel. Gen. Sosnkowski with a handful of units tried to pierce to Lwow; although they managed to destroy a German armoured column by night 16 September, they missed the goal. Meanwhile the Germans seized Wlodzimierz Wolynski, a town on the eastern bank of Bug. Whereas the Polish government and the Supreme Command had ventured as far as Zaleszczyki on the Romanian border.

On 17 September morning Soviet forces had crossed Poland's eastern border. To justify this decision the Soviet commissar for foreign affairs Vyacheslav Molotov had stated:

The Polish-German war has revealed the internal bankruptcy of the Polish state. After ten days of military operations, Poland has lost all its industrial areas and cultural centres. Warsaw, as the capital of Poland, no longer exists. The Polish government has collapsed and shows no sign of life. This indicates that the Polish state and government have, in effect, ceased to exist. In view of this state of affairs, the treaties concluded between Poland and the Soviet Union have no validity. Abandoned to its fate and deserted by its leaders, Poland has become a fertile field for all sorts of acts and surprises which could become a danger to the USSR. This is why, having preserved its neutrality until the present, the Soviet government can no longer remain neutral in the face of these facts.

Neither can the Soviet government remain indifferent when its Ukrainian and Byelorussian blood-brothers, inhabiting Polish territory, abandoned to their fate, are left without defence.

The Ukrainians and Byelorussians, often discriminated and persecuted in pre-war Poland, welcomed Red Armists as liberators. On 18 September in Stanislawow was declared independence of the Western Ukraine from Poland.

By night from 17 to 18 September Poland's state and military officials had crossed the Romanian border. According to international laws and the Belgian precedence from the First World War they were granted in France so-called droit de résidence, it means the right to accommodate in and operate from the French territory, whereas the Romanians, also allies, had to provide so-called droit de passage, it means the right of passage. But there was one person, who must not abandon the territory of a fighting country; it is the Supreme Commander, who as a militaryman is a subject to internment unless he has passed to the territory of a country also bound by the fight. Whereas Romania had declared her neutrality yet on 6 September; Marshal Edward Śmigły-Rydz had overlooked such a detail.

Meanwhile the Polish defence was extinguishing. Although there were still holding on Warsaw, Modlin, Hel, Brzesc and Lwow the resistance could not last forever. On 19 September capitulated Gdynia, on 20 September the Army Małopolska dispersed. On 22 September Lwow, which the Germans failed to seize, was handed over to the Russians. On 25 September in the battle of Tomaszow Lubelski got destroyed the northern grouping of Polish forces. Polish cavalry group heading to the Romanian border did not manage to pierce through the Soviet armoured columns on 27 September near Przemysl. On 28 September, heavily destroyed, burned, deprived of ammunition and supplies, capitulated Warsaw. Next day fell Modlin, and on 2 October - Hel. On 6 October the Independent Operation Group Polesie, which had been marching from beyond the Bug to Warsaw, after four days' successful battle of Kock, ran short of ammunition and got dispersed in St.Cross Mountains.

Poland fought 36 days with forces of 39 infantry divisions, 11 cavalry brigades and one armoured brigade. They obtained no support from the Allies. There was no formal cease-fire, no formal capitulation. The underground resistance was undertaken immediately.