Under Adolf Hitler's direction, the German military began the invasion of Poland on September 1st, 1939 to officially begin World War 2. The campaign lasted a little over a month despite a valiant Polish defense which was able to claim thousands of the Axis invaders, a complete German division and roughly a quarter of German air power in play. However, the defense of Poland was stifled by the September 17th invasion from the East by the Soviet Union under Josef Stalin - realistically, no nation of the period could have survived such a two-pronged invasion of such proportion. Polish military forces surrendered under heavy duress, bringing an end to formal combat actions, and the country was then divided in two by the victors. As no official government surrender took place (a government in exile was setup in London), Poles of all talents and walks of life continued to fight through the various organized and ad hoc underground/resistance movements which sought to enlist all manner of persons, weaponry and smuggling for the purposes of sabotage, assassination and disruption. The German occupation of Poland would last until the end of the war in 1945 to which Soviet forces moved in to begin the Polish period under communism. Poland would not gain its independence until 1991 following the fall of the Soviet Empire (1922-1991).
During World War 2, the Polish resistance was in constant action and, in 1942, its primary head was the Armia Krajowa ("Home Army"). To provide a cost-effective, home grown solution to help further the effort, an engineer by the name of Waclaw Zawrotny penciled a design for a crude-yet-simple submachine gun (SMG) that could be produced with a minimum of materials through basic assembly processes and without the need for heavy training and machinery. The weapon owed much to the simplicity and ease-of-use that was the British STEN - one of the most storied SMSs of the war - and was chambered for the standard German 9x19mm Parabellum pistol cartridge (the same as used in the MP38/MP40 submachine guns and the STEN). So resistance forces could use captured enemy ammunition stockpiles, the new submachine gun could be fed from readily-available MP-style box magazines. Major components making up the receiver were to be held together simply by way of threaded screws in an attempt to keep construction requirements to a minimum. Engineers completed a working prototype in September of 1943 to which secret tests were conducted in the woods of Zielonka, northeast of the capital city of Warsaw. The weapon was then formally adopted by resistance authorities and a schedule for serial production was put into place which would have numbered the thousands required. As the weapon was devoid of a true designator for ease of recognition, it was known as the "Blyskawica", meaning "lightning", and owed its name to the three downward-firing lightning bolts etched into prototype.
The Blyskawica certainly took the British STEN design to heart though it held two notable physical differences in its external configuration - it utilized a more traditional bottom feeding for its box magazine (as opposed to the STEN's side-mounted feeding) and incorporated a dedicated pistol grip with its trigger unit (the STEN utilizing its crude metal stock as the primary grip). Otherwise, it was clear that the Blyskawica was, in many ways, a STEN-influenced weapon for it retained an open-bolt, blowback system of operation, was chambered for the same 9mm cartridge and sported an identical tubular receiver. Ahead of the receiver was also a short section of perforated heat shield and barrel, the latter lacking any sort of muzzle detail. The trigger mechanics were contained in a STEN-like slab-sided housing while the butt was of a solid metal construction though holding a two-strut design patternand hinged to fold under the weapon for a more compact profile (reminiscent of the German MP SMG series).
Performance of the Blyskawica weapon included a rate-of-fire of 600 rounds-per-minute with a muzzle velocity of 1,300 feet-per-second. Effective range was recorded at 656 feet. Comparatively, the STEN managed approximately 500 rounds-per-minute with a 1,200 feet-per-second muzzle velocity, effective range being 330 feet. As in the STEN, feeding for the Blyskawica was by way of a 32-round straight detachable box magazine.
As can be expected with a product of this relative complexity, manufacture of Blyskawica submachine guns by underground workshops was slow and numbers limited based on the ambitious requirement. Only about 700 of the type were believed produced despite the thousands realistically required by the resistance. The weapon was naturally pressed into action almost immediately and known to have been used throughout various actions in an attempt to undermine German preparations for the upcoming Soviet offensives. The resistance intended to coordinate capture of strategic areas and recover useful supplies and material. To this was added the reestablishment of the Polish Army as well as reinstatement of Polish political/societal authority.
In reality, the Polish resistance plan met only a limited set of early victories but failed to net many of its primary overlying goals. The movement culminated in the famous and heroic "Warsaw Uprising" which ran from August 1st to October 2nd of 1944. Despite aid from the British Royal Air Force with limited help from the United States and the Soviets, the uprising was unsurprisingly crushed by the German occupiers which resulted in the deaths of many Poles and the total destruction of Warsaw itself. Advancing Soviet forces had halted just outside of the city during the fighting to allow German forces to subdue the rebels and pave an easier road for the Soviets to tackle the remaining, now-weary, Germans in turn. Some 600,000 Soviet troops would subsequently die in the taking of Poland.
Nevertheless, the Blyskawica proved itself a serviceable weapon considering its crudeness and wartime design/development environment. It held a short service life but was actively fielded alongside the better known STEN and other captured - or domestically-produced - weapons of the period. The Blyskawica proved a sound feat of Polish engineering that allowed for a glimmer of hope during a dark time in the country's long-running history. The type was quickly given up at the end of the war, replaced by more refined and modern post-war offerings, these primarily influenced by Soviet designs.