Although Below made more progress south of Arras, his troops posed less of a threat to the stronger Third Army than the Fifth Army, because the British defences to the north were superior and because of the obstacle of the old Somme battlefield. Ludendorff expected that his troops would advance 8 km (5 mi) on the first day and capture the Allied field artillery, "We chop a hole. The rest follows." Ludendorff's dilemma was that the parts of the Allied line that he needed to break most, were also the best defended. Much of the German advance was achieved quickly but in the wrong direction, on the southern flank where the Fifth Army defences were weakest. Operation Mars was hastily prepared, to try to widen the breach in the Third Army lines but was repulsed, achieving little but German casualties.
The Herts war diary reads,
The position gained was held stubbornly against all enemy attempts to retake it. On the morning of the 28th orders were received for a speedy evacuation of this line. The enemy at this point was well in our rear in possession of LAMOTTE so that the withdrawal had to be done quickly. The Bn showed the utmost resource during this dangerous manoeuvre, loosing [sic] very few men. The retirement took place in daylight through HARBONNIERS & CAIX. At the latter place the Bn attacked the enemy successfully but thereafter had orders to retire on COYEUX where it again assembled in a counter attack in which the acting Commanding Officer was wounded. During the day rearguard actions took place along the river bed to IGNAUCOURT. In the evening the Bn went into trenches in front of AUBERCOURT.(28 March 1918)
Day 9, 29 March
The Herts war diary reads, The enemy remained fairly quiet except for machine gun fire. (29 March 1918)
Day 10, 30 March
The last general German attack came on 30 March. Von Hutier renewed his assault on the French, south of the new Somme salient, while von der Marwitz launched an attack towards Amiens (First Battle of Villers-Bretonneux, 30 March – 5 April). Some British ground was lost but the German attack was rapidly losing strength. The Germans had suffered massive casualties during the battle, many to their best units and in some areas the advance slowed, when German troops looted Allied supply depots.
