Battle of Piotrków Trybunalski The Battle of Piotrków Trybunalski was a battle in the Invasion of Poland which started with the German breakthrough during the Battle of Borowa Gora . After the German breakthrough at Borowa Gora , the Germans and their tanks and soldiers headed for the Polish town of Piotrków Trybunalski . German tanks attacked the town , but Polish 155 mm howitzers destroyed several tanks and the Germans fell back , returning again later that day . The Germans managed to destroy 7 Polish tanks with artillery , but just after , they lost five of their Panzer tanks . After receiving several more direct hits and losing two more large Panzer tanks , the German tank crews simply ran away . Polish 7TP tanks pursued and kept beating the rest of the tanks off . The German soldiers now met the Polish infantry and attacked , but they were repelled by the Polish tanks . Soon , all the Germans retreated and by the end of September 6 , no hostile forces were in Piotrków Trybunalski . On September 7 , Marshal Rydz - Smigly orders the Polish forces to withdraw . Opposing forces . Polish Army . The core of the Polish force consisted of most of " Prusy " Army ' s Northern Group . The army , created as the main operational reserve of Polish commander in chief Marshall Edward Rydz - Śmigły was also the last to be mobilised in the summer of 1939 . Intended as a reserve of Łódź Army and Kraków Army , the Prusy Army was to support its ' neighbours and relieve them once the main German attacks are slowed down . However , the Battle of the Border did not gain the Poles enough time to fully mobilise the reserves . While most of Polish Army had been successfully mobilised prior to 1 September 1939 , on that date many sub - units of Prusy Army were still being formed or transported . By 4 September 1939 , when the German forces broke through the overstretched Polish defences , the Prusy army was far from battle - ready . It ' s Northern Group at that date consisted of 29th Infantry Division and Wileńska Cavalry Brigade , with 19th Infantry Division still being formed in the forests to the north - east of Piotrków Trybunalski while the 13th Infantry Division was still waiting for some of its ' sub - units near the railway hub of Koluszki and did not become available until September 6 . The army was strengthened by a mobile reserve formed by the 1st Light Tank Battalion ( armed with modern 7TP tank s ) stationed between Opoczno and Końskie , and the 81st Motorised Sappers Battalion . Apart from units of the Prusy Army , the Polish side also included a number of smaller units from Łódź Army . In the city of Piotrków Trybunalski itself the 146th Infantry Regiment was being mobilised for the 44th Reserve Infantry Division and was dispatched to the front as part of an improvised battle group under Col . Ludwik Czyżewski . In addition , elements of the Wołyńska Cavalry Brigade and the 2nd Legions ' Infantry Regiment of the 2nd Legions Infantry Division also took part in the battle as part of Col . Czyżewski ' s group . Wehrmacht . The German force fighting in the battle consisted of the entire XVI Panzer Corps . The unit , part of German 10th Army , was the strongest Panzer corps in the Wehrmacht and on 1 September 1939 included between 616 and 650 tanks of all types ( the entire Polish Army had 313 proper tanks altogether , not including reconnaissance tankette s ) . The XVI Corps included the 1st and 4th Panzer Divisions as well as the 14th and 31st Infantry Divisions .