 Complete the following phrase:  In the northwest, the German Army Group North under Fedor von Bock attacked Pomerania and Greater Poland, moving from Germany proper German Fourth Army and from East Prussia German Third Army. In the Battle of Tuchola Forest that lasted from 1 to 5 September, they split the Polish Army Pomorze under Władysław Bortnowski which was tasked with the defence of the Polish Corridor; parts of it under Admiral Józef Unrug would continue to defend pockets of the coast over the next few days or weeks at the Battles of 