Counter-offensive from the Wieprz

On the morning of 16 August 1920 a Polish attack set off from the lower Wieprz that decided the outcome of the Battle of Warsaw. Five infantry divisions and a cavalry brigade, assembled within a few days around Dęblin and Kock, struck north and north-east at the exposed left flank of the Soviet Western Front. They were led in person by the Commander-in-Chief, Józef Piłsudski. For three days Mikhail Tukhachevsky’s troops had been storming the Warsaw bridgehead, where Radzymin had fallen on 13 August, and now the Poles were coming out in their rear.

The strike group

The strike from the Wieprz was the heart of the plan adopted on 6 August. Of the two concentration areas proposed by the Chief of the General Staff, General Tadeusz Rozwadowski, Piłsudski chose the more distant one on the Wieprz, because it allowed him to strike not only at the enemy’s flank but at his rear. Within a week, in secret, troops withdrawn from the front on the Bug were moved here. From General Leonard Skierski’s (PL) 4th Army the group received the 14th Greater Poland Division, the 16th Pomeranian Division and the 21st Mountain Division, and from the 3rd Army the 1st and 3rd Legion Infantry Divisions and Colonel Feliks Jaworski’s cavalry brigade. According to Polish figures the 4th Army alone numbered 27,500 infantry, 950 cavalry and 90 guns. The highest commanders placed themselves with the divisions: Piłsudski with the 14th Division, Skierski with the 16th and General Edward Rydz-Śmigły with the 1st Legion Division.

Facing them stood the Mozyr Group (PL), which was to cover the left flank of the Soviet 16th Army along a long sector between the Vistula and the Bug. It was the weakest link of the Western Front. Russian accounts put its strength at about 21,000 men against Poles more than twice as numerous. The Soviet command did not expect a blow from this direction. It had taken the plan of the strike, found on 13 August on the body of a Polish officer, for a hoax.

The breakthrough

Near Kock and Cyców (PL) the divisions of the strike group broke through the weak defence without much difficulty and advanced north on a broad front. Progress on the first day was great: according to Russian assessments, by the evening of 16 August the Poles had advanced 35–40 kilometres. On the right flank the 3rd Legion Division took Włodawa on the Bug, the 1st Legion Division reached the line Wisznice–Wohyń, and the 21st Division together with the Greater Poland and Pomeranian divisions reached the river Wilga, took Garwolin and sent patrols towards Wiązowna. The group’s reserve was the 2nd Legion Division, brought over from across the Vistula.

That same day Colonel Stanisław Wrzaliński’s group, supported by tanks, moved out of the Warsaw bridgehead with orders to attack towards Mińsk Mazowiecki. At Radzymin the defenders repulsed another Soviet attack on the town, led by the commander of the 27th Rifle Division, Vitovt Putna. In the north General Władysław Sikorski’s 5th Army, which had been attacking from the Wkra for two days, took Nasielsk.

In Tukhachevsky’s rear

Tukhachevsky was directing his front from distant Minsk and for a long time did not understand what was happening on his left flank. Communications with his armies were failing, and Polish radio stations had been jamming the Soviet ones for several days. The 16th Army, still engaged before Warsaw, now had the Poles not in front of it but on its flank and in its rear.

The next day Polish units reached the line Biała Podlaska–Siedlce–Mińsk Mazowiecki and linked up with the defenders of the bridgehead. On 18 August Piłsudski issued orders in Warsaw for the pursuit, and Tukhachevsky’s armies began a disorderly retreat to the north-east. The strike from the Wieprz is regarded as one of the boldest manoeuvres of the war. In Poland a dispute soon began over who deserved the credit for it.