Reinforced with a second cavalry division, Eighth Army joined it with the one division already present to form an ad hoc corps. The two divisions helped kick off the main German assault with an attempt to roll up the Russian First Army's left flank. But the Russians had horsemen of their own charged with preventing just such a move.

The Germans rode forward with some enthusiasm, as this was the first time a large body of cavalry had been given a purely offensive mission in the East Prussian campaign. They ran into fierce resistance from the Russian 1st Cavalry Division, which slowed and finally stopped the German advance. Cavalry Corps Brecht would not be making deep operational penetrations on the first day of the offensive.