On 24 July Kleist defeated Reynier at the first battle of Uelzen. The French retreated to Munster and the Prussians occupied Uelzen. Both corps needed time to regroup and reorganize.
On the afternoon of 25 July the battle of Steinhorst was fought 15 miles to the south. 1st Prussian corps lost and retreated east, pursued by V French corps.
During the afternoon of 26 July Kleist received news of the battle, and on his own initiative ordered his corps to move south to occupy Steinhorst and pin V French corps between himself and 1st Prussian corps. At the same time Reynier ordered his cavalry to recce Uelzen
As night fell on 26 July Reynier became aware that the Prussians had vacated Uelzen and marched south, and Kleist received reports that French cavalry were approaching Uelzen. He realised that the loss of Uelzen would cut his lines of supply, and ordered his corps to about turn and march back to Uelzen.
Both corps still had casualties from their earlier battle. Both corps were badly deployed for battle. Both corps realised that possession of Uelzen would have a significant effect on the campaign.
The second battle of Uelzen opened with a race for the town, and the side that got there first and held it would win. If the Prussians failed to do so their lines of supply would be cut and attrition would quickly destroy 2nd corps. There are no alternative lines of supply available to Kleist.Table at 0800 27 July 1813