The Versailles Treaty set down in 1920 that the present system of fortification on borders with France, Luxemburg, Belgium and the Netherlands (and in the area of fifty kilometres east of Rhein) should be disarmed and torn down. This appointment was also related to certain localities along the coast of Baltic Sea. The situation in the east of Germany was a little bit more favorable. The existing works were decided to stay preserved in the state from 1918. This arrangement was unfortunately compiled in such unlucky way that immediately in the ongoing years several debates were led, if this appointment makes the pulling down of original fortifications and building of new more modern ones with far more significant fighting value actually impossible. Being this conclusion right or not the first after-war projects especially of personnel shelters for one or two launching forces started to arise already in autumn 1921. Steel concrete works with walls of one to one and half metre strength (ceiling of 0,8 m) were concerned. Till 1935 a substantional part of the projecting activity took place mainly in many offices adroitly tuck away in the hierarchy of Reichswehr. Being the construction on the west almost impossible, the attention turned to the fortification against an eventual attack from the area of Poland. It´s necessary to point out that right from the beginning it was not a defensive line, but it should have rather prevent from the disadvantages resulting from the two-front-war - i.e. if there was a land warfare with France, it would be very probable that its allies ( e.g. Poland or Czechoslovakia) would keep their contractual bonds and assault Germany. After an analysis of tactical postulates the most likely target of the opening attack seemed to be a lunge into the area of East Prussia, Pommern and Silesia. While Silesia stayed "almost" on the verge of concern and was fortified only very lightly, in Pommern and East Prussia large-scale lines of defense of stable works were projected. The last fortified system was the line between the rivers Oder and Warta (Oder- Warthe Bogen), which together with the Pommernwall (Pommernstellung) should have form a bridgehead of the Oder river. The reason was fully evident. If it happened to an unexpected lunge into Pommern and into the area between the Oder and the Warta rivers it would be very plausible that it would be managed to stabilize the front onto the line Nysa - Oder rivers and after demolishion of all bridges. That was unfavourable from two reasons. At first a very important traffic artery would be lost, which the Oder river is without question, and a counter attack would be very difficult across such a wide river. Therefore it was at most important to keep preferably a big brigdehead. And so in 1920- 1923 a fort ring Kostrzyno was updated, in 1926 a line of obstacles from Kostrzyno to Frankfurt on Oder (so-called Oder-Brückenkopfstellung) grew up and at last in 1934 - 1935 works on the line Nisczhlitz-Obra (so-called Nischlitz - Obralinie), which was during the following years enlarged into the strongest fortified area against Poland (so-called Oder-Warthe Bogen). Pommernwall (Pommernstellung) played the same role in Pommern although it has never reached such a strength like its southern neighbour.

In 1925 one fundamental turn happened, thanks to which it was possible to come from drawing boards to the use and to start building the first works. Till this year The International Controlling Commission, which oversaw the adherence of the arrangement of the Treaty of Versailles, had its branch-office in every "bigger" town. But all these controllers were canceled and only one of them stayed in Berlin. And so in December 1925 sappers instructions for the construction of new types of steel concrete works for the heavy machine-gun Maxim 08 were issued. At the same time three new concepts of fortifying originated. The first of them came from the presumption of modernizing the old forts, which concerned e.g. Kralovec or Kostrzyno. The main end was to intesify the depth of the defence and to secure greater infantry and anti-tank obstacles. The second concept was the system of nodal defence with its load to turn-off important ways and rail junctions to slow down the coming along forces by a construction of small steel concrete works and by prepared field-works. The third concept was the building of fortified areas with a huge number of strong works (panzerwerk), which would dispose of covering of flanks against circumvention. And thus in 1926 a construction in the surroundings of Kostrzyno and Glogow starts ( in both cases a new fortified line, in the case of Glogow it´s only a few kilometres far from Poland). It wasn´t managed to conceal the building activity. And thus the construction was very early uncovered by the International Controlling Commission. There was summoned a conference on this topic to Paris, which decided that the ban on construction holds for the whole East Prussia with an exception of the "Heilsberg triangle" (later there arose a huge defense line - Heilsberger Dreieck). The building was forbidden also on the whole territory east of the Oder river and in the case of Pommern there governs a fifty-kilometer-wide zone from the borders with Poland and from the sea - coast. By this arrangement de facto any fabrication was disabled in this area. From the already built cca 90 works approximately one third of them had to be pull down. On the other hand it was enabled to update the already existing fortifications, say even in the forbidden zones and on top of that there were also marked out the area, in which Germany could carry out a fort development. Concerning the Oderstellung only the defense line was shifted from the right bank to the left one.

In 1931 new projects of works for heavy machine-guns in armour-plates of 8-cm-strength arose. Also so-called armour casemates with a 10-cm-strenght armour were put into operation. The machine-guns Maxim 08, Maxim 13 and Maxim 15 made for mounting. In the area of the Oderstellung about 80 small steel concrete works (pillboxes and also shelters) with at most two rooms were built. They were placed mainly near railway and road bridges, near shallows and ferries.

The year 1933 passed over in token of great changes in the whole Germany. Adolf Hitler came into power, he didn´t conceal his attitude to the Treaty of Versailles. In terms of his arrangement for avoidance of unemloyment a number of fatigue-parties rise (FAD), which were set to creation of obstacles and to dirt moving. In August 1933 directives for the construction of new classes of works in hardnesses A to D with specified depths of walls and ceilings were issued. At the same time the first standardization of armour-plates, door, high of rooms, corridors etc. took place. There also came to the first use of armoured dome with one to six gunports ( in the Oderstellung was used wholly the armoured cupola 3aP7). In the following years the fortification of the whole lenght of the Oder river in the area Wroclaw - Krosno finally started. The first line of works was placed right on the verge of the river, eventually it was "built in" the flood-protection bank. Moreover in the most endangered places there´s the second line created 500- 1500 metres far away, where the crux of defence lies in the works designated for the direct fire of 1- 2 heavy machine-guns. Compared to the small works, raised in the first line, the personnel found here far more comfort, often there was as a part a dormitory for advanced forces acting in the immediate surroundings. Aside from the eye-sights in armoured-plates the observation could have been also carried out with the periscopes in the armoured-plates placed on the ceiling beams of the works, and later especially with the observational cupola 9P7. In the case of the Oderstellung personnel shelter for 1-2 launching forces play also an important role. In the endangered places the shelters could also dispose of the observational cupola, eventually of the periscope in armoured-plate. During the whole time the field-work was also built that, especially in less enterable areas, created the spine of the defence.

It´s necessary to remark that the construction of the Oderstellung has never lured a big attention, so compared to other lines it has slightly prolonged . Yet about 650 works of different types, endurances and purposes were managed to be finished in this territory.