In March 1939 year, the supreme command of Germany began work on “Case Weiss”, that is, the operational plan for the war with Poland. However, the plans for the attack had been developed before, however, only from that point on did they become official. In plan “Case Weiss” old strategies were included, as well as new, created before 1939 a year.
According to preliminary assumptions, The Wehrmacht had to conquer Poland in the shortest possible time, or at least make it so, to be sure, that she would lose this war. Hitler spoke: “within 8 do 14 days for the whole world must become clear, that Poland is in danger of collapsing; the operations themselves may of course take longer (6-8 weeks)”. This haste was dictated by the necessity to leave the eastern border almost unguarded (only Army Group remained there “C” in the lineup 34. reserve infantry division, low-waisted and poorly trained), due to the need to send most of the troops to Poland. German generals took into account the possibility of an offensive led by French troops, resulting from that country's commitments to Poland. For this, it would be necessary to conquer this country as soon as possible. It would make it possible to show France, that it makes no sense to intervene (because Poland would already be in a lost position) or – in the event of the launch of attacks by French troops – quick transfer of German troops to the western border. The developed Blitzkrieg technique would help in mastering Poland quickly, however, the relevant operational plans also had to play an important role. Therefore, for the proper preparation of the operation “Case Weiss” great importance was attached.
According to the operational plan “Case Weiss”, German forces directed against Poland, counting 60 Great Entities, were to be divided into two Heeresgruppe (Army Group): “Midnight”, in the lineup 3. i 4. Army and “South”, consisting of 8., 10. i 14. Army. As the name suggests, Army Group “Midnight”, General Fedor von Bock, was to attack Poland from the north, being located in Pomerania and East Prussia. The Army Group, on the other hand “South”, under the command of General Gerd von Rundstedt, attacking from the south, located in Lower Silesia and Slovakia.
In the first phase of the campaign, 3. Army of General Georg von Kuehler, starting from East Prussia, it was supposed to eliminate the points of Polish resistance in northern Mazovia. On the other hand, the 21st Corps, which was part of it, was to move to the east, in order to connect to 4. Army of General Hans von Kluge, aimed at liquidation “corridor” dividing Pomerania and East Prussia, thus isolating the Polish part of Pomerania. Another task 4. Army, after merging with the XII Corps, it was breaking through to Warsaw along the Vistula.
Request 8. Army, General Johannes Blaskowitz, located in the northern part of Lower Silesia, in the vicinity of Zielona Góra, it was purely protective. From the north, the army was to provide communication with 4. The army and prevent Poles from isolating it, while from the south it was to constitute a defensive force for the left wing of the main storming unit – 10. Army of General Walter von Reichenau. 10. The army was by far the strongest of all those involved in the campaign. It consisted of up to 6 infantry divisions, 2 armored divisions, 2 motorized divisions and 3 light divisions, it was equipped with half of all tanks intended for combat in Poland. Its task was to lead the main attack, going straight to Warsaw. It was supposed to cover her from the south 14. Army of General Wilhelm List, aimed at, bypassing the Silesian fortifications, mastering Małopolska.
Entire operation, in accordance with the assumptions of the Blitzkrieg, two Air Fleets were to protect them from the air (Air fleet): 1. (General Albert Kesselring) i 4. (General Alexander Loehr). Their primary task was to eliminate Polish aviation, and then the destruction of all communication routes combined with covering your own troops. After completing these tasks, Luftflotten was to destroy any goals with economic value, such as factories, or other industrial plants.
also, in the area occupied by the Polish army, which would not yet be overrun by the Wehrmacht, subversive troops were to operate – the so-called. In the Column.