In the initial weeks of Operation Barbarossa, Army Group South had rapidly advanced East, defeating several Soviet mechanized corps at the Battle of Brody 23–30 June.
On 7 July, XXXXVIII Motorized Corps cracked a weak defense on the Stalin Line and began to move rapidly, embracing the right flank of the 6th Army.
Such a decision left the possibility, instead of a strike to the southwest, to continue the offensive from Kiev farther east, beyond the Dnieper River.
So, in the opening days of Battle of Uman the task of encircling the 6th and 12th armies from the north and the east was to be done by divisions of the XXXXVIII Motorized Corps only.
The advance of the 11th Field Army from the Soviet-Romanian border was suspended by Soviet counterblows, and its attack from the south towards Vinnytsia was postponed.
[citation needed] The Axis forces were divided into those of 1st Panzer Group that had suffered significant losses in matériel, but retained combat effectiveness, and the large infantry formations of the German and Romanian armies that attempted to advance from the West to meet the armored troops north of Crimea, the initial strategic objective of Army Group South.
[citation needed] Since 15 July, the XLVIII Motorized Corps of Wehrmacht repulsed the counter-attacks of the Soviet "Berdichev Group" and resumed the offensive.
On the left, the 11th Panzer division was in the gap between Soviet armies, so by 16 July it made a deep (70 km) breakthrough to the South-East.
At the same time the 17th Field Army from the West was approaching too quickly and Halder feared that the future "cauldron" would not trap significant enemy forces.
[7] Meanwhile, the 17th Field Army tried to implement a shortcut version of the original plan, according to which the Soviet troops were to be surrounded to the west of Vinnytsia.
But now Germans had no mobile units to hit Vinnytsia from the North (they operated east of Berdichev), and the offensive of 11th Field Army from the south was postponed.
[8] By 18 July, the Soviet command realized that they did not have enough forces to seal the breakthrough of the 1st Panzer Group and restore the defense along the "Stalin Line".
Units of the Army Group "Center", instead of attacking Moscow, had to hit the South and North to surround the Soviet troops and prevent their withdrawal.
By stopping the advance of the German strike wedge, Soviet troops were able to continue the retreat, although the gap with the 26th Army remained.
[13] To the west of Uman, the command of the XXXXIX Mountain Corps launched the fresh 125th Infantry Division, which took the town of Gaisin on 25 July.
Other parts of the Corps rushed into the breakthrough, and the 1st Mountain Division achieved the greatest success – on 26 July it advanced 70 kilometers to the south-east and found itself in the rear of the Soviet troops.
The Soviet command mistakenly believed that the Germans would immediately move to the east, to the crossings over the Dnieper, thus the attacks of the 6th and 12th armies from the flank would hamper them.
[citation needed]But the commander of the Southern Front, Tyulenev, assured Stalin that the situation would be restored by a blow towards Ponedelin Group of the fresh 223rd Rifle Division from the northeast, and the units of 18th Army from the south, while denying any supply difficulties.
At this time, other parts of the XXXXVIII and XIV Corps in heavy fighting repulsed all attempts of the Ponedelin Group to break through to the east and north-east.
The encirclement was reinforced the next day by a second joining, formed when the German 16th Panzer Division met the Hungarian Mobile Corps in Pervomaysk.
However, the command of the Southern Front repeatedly ordered to move to the east, to the border-line on the Sinyuha River, which was firmly occupied by the troops of the XXXXVIII and XIV Motorized corps.
On August 1—5, the Ponedelin Group attacked mainly in this direction and only some parts of the 6th Army moved to the south and southeast, entering into a head-on battle with the XXXXIX Mountain Corps.
[citation needed] On 4 August, German troops, by a blow from both sides, eliminated the bridgehead captured by the Soviet units (General Proshkin's group) on the eastern bank of the Sinyuha River near the village of Ternovka.
[23] By the evening of 4 August, the High Soviet Command had virtually lost interest in the fate of the remnants of encircled armies.
This time they struck south, assuming that it is enough to break through the positions of the XXXXIX Mountain Corps to connect with the units of the 18th Army to the north of Pervomaysk.
Detachments of the 1st and 4th Mountain divisions failed to stop the night breakthrough, the Soviet strike forces marched 20 km and even took Golovanevsk.