In a classic pincer maneuver, the XL Reserve Corps from the German 8th Army was sent along the Bobr River to meet the forward elements of the 10th with the goal of trapping the majority of the our 10th (III, XX, and III Siberian Corps) in a cauldron.  While the XX Corps desperately tried to hold the German onlaught in the Augustow Forest, the fortress of Osowiec was the hinge of the Russian left flank.

With the XX Corps destroyed, you have held the front at the Bobr River, maintaining cohesion of our lines.  Your troops are to report to the rear for reorganization and preparation for their next assignment.
