Battle of the Niemen begins

On the morning of 20 September 1920 two Polish divisions supported by heavy artillery came out of the woods of the Augustów Forest and attacked the Soviet positions in front of Grodno. So began the Battle of the Niemen, the Polish Army’s second great operation against Mikhail Tukhachevsky’s Western Front after the Battle of Warsaw. The attack at Grodno was only the first move. The decision was to come from the north, where the 2nd Army’s manoeuvre group was to outflank the Niemen line through land held by the Lithuanians.

After Warsaw

After the August defeat Tukhachevsky’s troops fell back to the line of the Niemen, the Shchara and the Svislach. They had not been destroyed. Within three weeks the front commander filled up his divisions with reinforcements from the interior of Russia and prepared a new attack on Białystok, Brest-Litovsk and on to Lublin. In the south the Poles had already beaten Budyonny’s cavalry at Komarów, but in the north the initiative could still pass back to the Russians.

Józef Piłsudski decided to forestall them. On 10 September, at his headquarters in Brest-Litovsk, he explained the plan of the operation to the commanders of the 2nd and 4th Armies, and he issued the detailed order on 19 September. General Leonard Skierski’s 4th Army was to attack Wołkowysk, and General Edward Rydz-Śmigły’s 2nd Army was to pin the enemy down at Grodno. The manoeuvre group, made up of the 1st Legion Division, the 1st Lithuanian-Belarusian Division and two cavalry brigades, was to march through Sejny and Druskininkai into the Russian rear around Lida. The troops were to march by night, without supply trains, and the whole operation was to remain a secret not only from the enemy but also from the Western powers.

The attack on Grodno

The task for 20 September went to General Andrzej Galica’s (PL) 21st Mountain Division and Colonel Adam Koc’s 22nd Volunteer Division, supported by General Ignacy Ledóchowski’s heavy artillery group. According to Polish accounts they numbered about 11,600 men and 107 guns in all. Their attack was to improve the position before the main blow. The surprise was complete. The Soviet 5th and 6th Rifle Divisions hastily withdrew to the forts of the fortress of Grodno. The Volunteer Division came up to the forts, and the Mountain Division took Kuźnica.

The soldiers on the Niemen itself faced a river swollen by the autumn rains. Second Lieutenant Janusz Kozłowski of the 205th Volunteer Infantry Regiment recalled how his platoon dug in at night on the high bank and how at dawn the factory chimneys of Grodno emerged from the mist. The sappers tried to set up trestles for a bridge, but the current kept overturning them. “We froze to the marrow in the trench overnight; after the summer campaign we had no warm clothing,” he wrote.

Tukhachevsky took the attack at Grodno for the start of the main Polish offensive. He ordered the army reserves to be brought up and the Poles to be stopped. The next day Soviet divisions counter-attacked at Kuźnica and Nowy Dwór, and in the following days the fighting spread to the whole sector from Grodno to Brzostowica. This was exactly what Piłsudski wanted: the more forces the Russians tied down at the fortress, the weaker their defence in the north, from where the manoeuvre group was to set off on 22 September.

The League of Nations and Riga

That same day the Council of the League of Nations adopted a resolution confirming the so-called Foch Line in the Suwałki region as a provisional demarcation line between Poland and Lithuania. The Polish plan meant crossing it. The Lithuanians, who had occupied Vilna after the Red Army’s retreat and in September had fought the Poles near Sejny and Augustów, declared their neutrality in the Polish–Soviet war. In Poland, however, they were regarded as Moscow’s de facto allies.

On 20 September in Moscow Vladimir Lenin told his associates that a quick armistice with Poland was needed, because first the White army of General Pyotr Wrangel had to be defeated in the south. The next day Polish–Soviet peace talks were to begin in Riga. Their course now depended to a large extent on what would happen on the Niemen.