After reaching the Vistula River Aug 1944, Soviet troops had slowed its advance, building up men and supplies in eastern Poland before launching the next offensive. On 12 Jan 1945, a large invasion force of 163 divisions with a total of 2,203,000 men, 4,529 tanks, 2,513 self-propelled guns, and 13,763 artillery pieces, supported by about 5,000 aircraft, was launched for the Vistula-Oder Offensive. The attacking force consisted of Marshal Georgi Zhukov’s 1st Byelorussian Front and Marshal Ivan Konev’s 1st Ukrainian Front. Facing the attack was Colonel General Josef Harpe’s German Army Group A, consisted of three armies (4th Panzer Army, 9th Army, and 17th Army) totaling 400,000 men, 1,150 tanks, and 4,100 artillery pieces.
The first attack in the offensive took place at 0435 hours on 12 Jan with Soviet 1st Ukrainian Front forces attacking out of the bridgehead at Baranów, Poland against positions held by troops of XLVIII Panzer Corps of German 4th Panzer Army; after a heavy artillery barrage, infantry followed up with probing attacks. At 0830 hours, the Soviet 1st Byelorussian Front launched its attack from the Magnuszew bridgehead (by Soviet 5th Shock Army and 8th Guards Army) and Pulawy bridgehead (by Soviet 33rd Army and 69th Army) following a heavy artillery barrage; as they opened gaps in German 9th Army’s defenses, tanks of Soviet 1st Guards Tank Army and 2nd Guards Tank Army were sent in to penetrate into the German rear, moving toward Lódz and Sochaczew, respectively. At 1000 hours, the second round of artillery barrage began at Baranów, and four hours later the Soviet 1st Ukrainian Front launched a second attack, this time overwhelming the German lines and creating several gaps. On the same day, the Soviet 1st Army, 61st Polish Army, and 47th Army encircled Warsaw, Poland.
Over the course of the following few days, many German defensive positions in eastern Poland became cut off, but by the time Soviet forces reached Kielce, they had suffered serious casualties and needed time to regroup. On 14 Jan, Soviet 1st Ukrainian Front crossed the Nida River and moved toward Radomsko and the Warta River in central Poland.
On 15 Jan, Adolf Hitler intervened with tactical decisions and ordered the Panzerkorps Grossdeutschland to counterattack from East Prussia, Germany toward the positions held by the German 4th Panzer Army; this counterattack was launched against the advice of German General Heinz Guderian. The counterattack was repulsed by troops of the 1st Byelorussian Front, forcing the attackers to withdraw to the southwest.
In the evening of 16 Jan, German troops evacuated from Kielce. On the following day, 17 Jan, Warsaw was captured by Soviet troops. Hitler was furious at the abandonment of Warsaw after he had given the order to fight until the last man; he issued the order for the arrest of Colonel Bogislaw von Bonin, head of the Operations Branch of the German Army High Command, and for the sacking of both General Smilo von Lüttwitz of German 9th Army (to be replaced by General Theodor Busse) and General Walter Fries of XXXXVI Panzer Corps.
On 17 Jan, Konev received orders for his Soviet 1st Ukrainian Front to march toward Breslau, Germany (now Wroclaw, Poland) and capture the industrial region of Upper Silesia. En route, his troops captured Kraków unopposed on 19 Jan.
On 18 Jan, Soviet troops reached Lódz, Poland, capturing the city on the following day.
On 20 Jan, Colonel General Ferdinand Schörner replaced Colonel General Josef Harpe as the head of German Army Group A. On 22 Jan, after four days of confusion and racing to prevent envelopment, the remnants of the German 4th Panzer Army successfully fled to the Oder River; by that time, Soviet forces had already reached the river at a few spots also, establishing several bridgeheads. On 25 Jan, Posen, Germany (now Poznan, Poland) became the target of a new Soviet 1st Guards Tank Army and 8th Guards Army attack, starting a long period of brutal street fighting in that city. Also on 25 Jan, General Friedrich Schulz of German 17th Army requested permission for his remaining 100,000 men to withdraw from Katowice, Poland, which was refused; he requested the same again on the following day, finally receiving authorization from Schörner. On 27 Jan, Soviet troops reached the Auschwitz Concentration Camp. German 17th Army completed its evacuation of Katowice in the night of 27 Jan, and troops of the Soviet 1st Ukrainian Front entered the city on 28 Jan. On 31 Jan, Soviet troops captured Kienitz, Germany on the west bank of the Oder River.
After the offensive had generally stalled since 31 Jan, on 2 Feb 1945 the Soviet Stavka declared the operation complete. Although Zhukov realized that Berlin, only 70 kilometers to the west, was only lightly defended at this point, he was a supporter of the Stavka’s decision to stop the offensive, for that the parallel offensives in East Prussia and Pomerania should be brought to a conclusion to secure the northern flank. General Vasily Chuikov was among the chief proponents of continuing the offensive, but this group would not get their wish. According to Soviet history, the offensive cost the Soviet forces 43,476 killed and 150,715 wounded, while killing 150,000 and capturing 70,000; these statistics should be taken in the consideration that Soviet reports at the time tended to under-estimate Soviet casualties and over-estimate that of the Germans.