this was to be carried out by army group south commanded by general gerd von rundstedt , attacking from german silesia and from the moravian and slovak border : general johannes blaskowitzs 8th army was to drive eastward against d ; general wilhelm lists 14th army was to push on toward krakw and to turn the poles carpathian flank ; and general walter von reichenaus 10th army , in the centre with army group souths armor , was to deliver the decisive blow with a northeastward thrust into the heart of poland .