This article is about the war in 1919. For the Soviet invasion of Poland in 1939, see Soviet invasion of Poland.
Despite Poland not even a year old yet, nevertheless got dragged into war with a new SFSRball. Agianst all odds, Polandball remain independent and prevent annexation, though Polandball was exhausted from fighting and his victory didn't deter future aggression which would happen twenty years later in 1939 with the Invasion of Poland.
The Peace of Riga was established in 1921, dividing Belarusball between Second Polish Republicball and Russian SFSRball. Russian SFSRball gained clay, but his revolution was stopped from spreading until World War II and its aftermath.
Polandball itself had seen the loss of its clay throughout the 18th century due to the partitioning of Polish-Lithuanian Commonwealthball's clay by Prussiaball, Russian Empireball, and Austrian Empireball which saw an end to the commonwealth by the start of the 19th century. During World War I, many Poles fought for both the Entente and the Central Powers, but all gathered to Second Polish Republicball after it was declared on November 11th, 1918 at the end of World War I due to Polandball no longer being ruled by a foreign power. Polandball took land from the defeated German Empireball after the war ended due to the Allies giving him land, but wanted to get more clay by expanding eastward.
Meanwhile in Russia, the Russian Civil War was in full swing and Russian SFSRball was busy fighting against White Movementball, Free Territoryball and other separatist forces. In 1919, both Russian SFSRball and Ukrainian SSRball invaded Ukrainian People's Republicball and began pushing towards Polandball which caused him to mobilize his forces and push into Eastern Europe.
Polish Offensives of 1919
Polandball went on the offensive and attacked Russian SFSRball as early as February 1919 while he was still busy fighting against White Movementball. Russian SFSRball sent its Red Army to attack the Poles and while they did gain ground, they were ultimately forced back. The Red Army was forced to withdraw due to offensives from White Army forces and the Polish troops advanced into Belarusball occupying much of his clay. Polish troops made it into Western Ukraine and grouped up with the armies of the Ukrainian People's Republic and occupied both Kievball and Brodyball. Despite these gains, Polish and Ukrainian troops were ill-equipped to satisfy their aspirations.
By 1920, the situation for Russian SFSRball had improved as the bulk of the White Army had been defeated and now had fresh troops to send off to fight against the Poles as other fronts in the Russian Civil War were not stabilized. At the beginning of the war, both sides had around 50,000 men in total, but the Red Army soon managed to assemble hundreds of thousands of troops and began sending them to the Polish Front. The Polish and Ukrainian forces meanwhile prepared for a push into Eastern Ukraine codenamed Operation Kiev.
This resulted in the Kiev Offensive and was carried out by Polish and Ukrainian troops on April 24th, 1920. The offensive saw gains into Bolshevik held territory, but the Red Army continued sending reinforcements to the front and before long, the attack stalled. The Red Army pounded the attacking forces until they broke the Polish lines on June 5th and forced them into a retreat and advanced into Western Ukraine and close to the Polish border.
Soviet Offensives of 1920
Following the Soviet victory at the Kiev Offensive, the Red Army went on the offensive and began pushing into Eastern Poland. Alexy Brusilov, the last commander-in-chief of the Imperial Russian Army and head of the Brusilov Offensive, made an appeal to all former Tsarist army soldiers to join the Red Army and Lenin called on citizens to join. These calls saw hundreds of thousands of fresh volunteers and reinforcements heading off to the front, the latter of which was overstretched and lightly defended by the Poles who could only muster up 120,000 soldiers. The Red Army began pushing into Polish held territory and exploited their weaknesses such as numerical inferiority compared to their Soviet counterparts, especially in crucial areas.
Polish troops used "German Trenches" to hold off Soviet attacks, but their numerical disadvantage was exploited by the Soviets who overran these defensive fortifications. Vilniusball was captured on July 14th and the Poles were forced to retreat again and Brest-Litovsk fell on July 19th in Belarus. The Red Army was advancing at a rate of 32 kilometers a day and the Poles were being forced back further and further towards Warsawball. Poland gathered what forces it could and had them sent to Warsaw where a climactic battle was about to begin and Poland's independence was at stake.
Battle of Warsaw
Main Article: Battle of Warsaw
By the end of July, the Red Army stood at the gates of Warsaw and launched an assault on the city on August 3rd, 1920 which was repelled, but the battle was just beginning of the battle. The Soviet commander, Mikhail Tukachevsky, was certain that all was going to plan, but was unknowingly falling into a trap set up by the Poles after they managed to intercept Red Army radio communications.