The battle itself was a part of a larger Soviet Spas-Demensk offensive operation with the aims of clearing the eastern bank of the Dnieper River of German forces and piercing the Panther-Wotan line of defences.

The relief never arrived; after two days the Polish 1st Tadeusz Kościuszko Infantry Division suffered 25% casualties and had to be withdrawn, while the remaining Soviet forces were too weak to widen the achieved breakthrough.

As the Germans were aware of the Polish and Soviet plans, they reinforced their lines in the area with elements of the 36th Infantry division under Gottfried Fröhlich[3] just a day before the launch of the offensive.

The swampy valley of the Mereya River (often written as Miereja in Polish historiography), lay in front of the German positions.

The main task of the Polish 1st Infantry Division was to break through the German defences on a two kilometre front in the vicinity of the village of Polzukhi and Hill 215.5.

In the second stage of the operation, Polish forces were to reach the line of the Pnevka river and then continue the assault towards Losiev and Churilov.

[4][5] Three days prior to the actual battle, on 9 October, General Zygmunt Berling, the commanding officer of the Polish 1st Division, ordered a force recon assault on the German lines.

In addition, the Germans reported no less than 1,000 Polish and Soviet soldiers who crossed the lines prior to the battle for fear of being sent back to the Gulag when the war was over.

At 5:50 a.m. the 1st battalion left its positions and started to push towards the Mereya River and the German trenches located 200 metres further westwards.

By noon, although the Polish 1st Division had managed to strike a three kilometre deep wedge into the German lines, the assault had to be halted.

The swampy river valley proved to be a problem to artillery as well: light infantry guns and mortars had to be carried by foot soldiers as wheeled transport could not cross the obstacle.

Aided by the Luftwaffe and reserves of the German 39th Corps, the formation stormed Polish positions at Trigubova, which were held by the 2nd battalion of the 1st Regiment.

The initial attack was held off, but in the end German tanks and complete aerial superiority forced the Poles to abandon their positions.

A series of attacks and counter-attacks proved costly to both sides, but changed little: despite all-night close-quarters fighting, the villages of Trigubovo and Polzukhi remained in German hands.

On the night of 12 October, the Polish scouting troops launched a surprise assault on the village of Tregubova and successfully destroyed the headquarters of the German 337th Infantry Division.

The expected German surprise Lenino offensive was lost, and the Polish and Soviet forces also suffered considerable losses.

Zygmunt Berling believed that with the number of casualties on both sides that Soviet advantage was lost and instead they should switch to a defensive mode; his suggestion was unilaterally rejected.

The Polish division had held its sector for two days, despite sustaining heavy losses, after which it was returned to the second echelon of the Front for rebuilding.

[citation needed] Despite heavy losses, the Soviet-Polish troops managed to keep the Lenino bridgehead, which later played a considerable role in Operation Bagration.

[citation needed] In military aspect, the plan to capture the bridgehead base of Lenino was reasonable, but the timing of the offensive was not suitable.

At the end of 12 October, casualties of the Soviet and Polish troops had already been unacceptable, and the important Hill 217.6 height could not be taken although the last reserved force had already been used up.

The ZPP leaders wanted to prove before the Tehran conference took place that Polish units in the USSR could take an active role in the fight against the Germans.

[1][17] Some authors go as far as to suggest that the decision was a deliberate attempt to further exterminate Poles in the Soviet Union, akin to the Katyn massacre, but this time by German hands.

[4][18] After the victory of the Czechoslovak troops at the Battle of Sokolovo, this was the second time that a foreign force trained by the Soviet Union participated in the Soviet-German front.

This Polish force, sometimes called "Berling's Army", played an important role in the fight against Nazi Germany and the capture of Berlin.

After the war, the village of Trigubovo was renamed Kostyushko, a Russian language rendering of the name of Tadeusz Kościuszko, the name-sake of the Polish division.

[5] On 7 October 1950, the anniversary of the battle was declared the official "Day of the Polish Army" by the authorities of the People's Republic of Poland.