The Battle of Tuchola Forest (German: Schlacht in der Tucheler Heide, Polish: Bitwa w Borach Tucholskich) refers to one of the first battles of the Second World War during the Invasion of Poland, 1939. The battle started on 1 September and ended on 5 September with a major German victory. Due to lack of coordination and poor command of forces on the Polish side and German numerical and tactical superiority, the Germans managed to cripple the Polish Army of Pomerania and connect mainland Germany with East Prussia, breaking through the Polish Corridor.