the XXI (Maj. Gen. Frank W. Milburn), was relatively new, having joined the army in January. As the Seventh Army offensive began, the basic question was how stubbornly the Germans would defend before falling back on the Siegfried Line. Only General Milburn's XXI Corps — on the Seventh Army's left wing, near Saarbrücken — was fairly close to the Siegfried Line, while other units were as much as away. Making the army's main effort in the center, General Haislip's XV Corps faced what looked like a particularly troublesome obstacle in the town of Bitche. Surrounded by fortresses of the French Maginot Line, Bitche had been taken from the Germans in December after a hard struggle, only to be relinquished in the withdrawal forced by the German counteroffensive. On the army's right wing, General Brooks's VI Corps—farthest of all from the Siegfried Line—first had to get across the Moder River, and one of Brooks's divisions faced the added difficulty of attacking astride the rugged Lower Vosges Mountains. Two German corps and part of a third were in the path of the impending American drive. At Saarbrücken, the left wing of General Knieß′ LXXXV Korps would receive a glancing blow from Milburn's XXI Corps. Having recently given up the 559. Volksgrenadierdivision to the 7. Armee, Knieß had only two divisions, one of which was tied down holding Siegfried Line positions northwest of Saarbrücken. Southeast of the town, with boundaries roughly coterminous with those of Haislip's XV Corps, stood the XIII SS Korps (SS-Gruppenführer und Generalleutnant der Waffen-SS Max Simon) with three divisions. Extending the line to the Rhine was the XC Korps (General der Infanterie Erich Petersen) with two volksgrenadier divisions and remnants of an infantry training division. Although the Germans worried most about a breakthrough in the sector of Petersen's XC Korps into the Wissembourg Gap rather than through Simon's XIII SS Korps into the Kaiserslautern corridor, the shifts and countershifts made in preceding weeks to salvage reinforcements for the 7. Armee actually had left the XIII SS Korps the stronger. In addition to two Volksgrenadier divisions, Simon's corps had the 17th SS Panzergrenadierdivision, at this point not much more than a proud name, but a unit possessing considerably more tanks and other armored vehicles than were to be found in the entire adjacent corps. The American main effort thus aimed at the stronger German units, though at this stage of