'Lüttich' was the German counter-offensive in the Mortain area of north-western France against the 'Cobra' break-out from the Normandy lodgement by the US formations of Lieutenant General Courtney H. Hodges’s US 1^st Army and Lieutenant General George S. Patton’s 3^rd Army of Lieutenant General Omar N. Bradley’s 12^th Army Group (7/13 August 1944).

The counter-offensive was ordered by Adolf Hitler as the means to eliminate the gains made by the US 1^st Army during 'Cobra' and the subsequent days and, by reaching the coast in the region of Avranches at the base of the Cotentin peninsula, to cut off the formations of the US 3^rd Army which had advanced into Brittany.

The main German striking force was General Hans Freiherr von Funck’s XLVII Panzerkorps of SS-Oberstgruppenführer und Generaloberst were Waffen-SS Paul Hausser’s 7^th Army, and for the operation the Panzer corps had one and a half SS Panzer divisions and two army Panzer divisions. Although their attack made initial gains against Major General J. Lawton Collins’s US VII Corps, the Germans were soon halted and Allied warplanes inflicted severe losses on the attacking forces, eventually destroying nearly half of the German armour involved in the attack. Although fighting continued around Mortain for six days, the US forces had in fact regained the initiative within one day of the German attack’s start.

The German commanders on the spot had vainly warned Hitler that there was at best very little chance of the attack succeeding, and the concentration of the German armoured reserves at the western end of the front in Normandy soon led to disaster, as they were outflanked to their south and the front to their east collapsed, resulting in many of the German troops in Normandy being trapped in the Falaise pocket.

On 25 July, after six weeks of attritional warfare on an essentially stalemated front, US forces under the overall command of Lieutenant General Omar N. Bradley undertook the 'Cobra' offensive which broke through the German defences just to the west of St Lô. Almost the entire western half of the German front in Normandy collapsed, and on 1 August US forces took Avranches. With the capture of this town at the base of the Cotentin peninsula, and also an intact bridge at nearby Pontaubault, the US forces had destroyed the German ability to anchor the western end of their Normandy front on the sea, and could therefore advance to the west and south into Brittany. Patton’s US 3^rd Army was activated the same day. Despite German air attacks on the bridge at Pontaubault, Patton pushed no less than seven divisions across it during the next three days, and units of his army began advancing almost unopposed toward the ports of the Breton coast.

From 30 July, Lieutenant General Sir Miles Dempsey’s British 2^nd Army undertook the 'Bluecoat' supporting attack on the eastern flank of the US armies, and a sizeable proportion of the German armoured reserve being rushed to the west in an effort to stem the US breakthrough were diverted to face this new threat. The US forces meanwhile continued their attacks to widen the corridor around Avranches. Although the Germans held the vital road junction of Vire, Collins’s VII Corps took Mortain, 19 miles (31 km) to the east of Avranches, on 3 August. On the following day, while Major General Troy H. Middleton’s VIII Corps continued to advance to the west through Brittany toward the major ports of Brest and Lorient, Bradley ordered Patton to use most of his 3^rd Army’s strength in a drive to the east round and past the open German flank and thus into the German rear areas. Major General Wade H. Haislip’s XV Corps advanced no less than 75 miles (120 km) during the next three days, and by 7 August was nearing Le Mans, formerly the location of the 7^th Army's headquarters, still an important German logistics centre.

The Oberbefehlshaber 'West', commanding on the Western Front, was Generalfeldmarschall Günther von Kluge, who had succeeded Generalfeldmarschall Gerd von Rundstedt in this post on 5 July, and on 17 July, after Generalfeldmarschall Erwin Rommel had been injured by an Allied air attack, von Kluge also assumed direct command of Heeresgruppe 'B', the formation commanding the German forces in the battle for Normandy. von Kluge had warned Hitler on 22 July that the collapse of the front in north-western France was imminent, but Hitler continued to order him to hold without thought of retreat.

On 2 August, Hitler sent von Kluge a directive ordering an immediate counter-offensive from Mortain and Avranches. General Walter Warlimont, the deputy chief-of-staff at the Oberkommando der Wehrmacht, was also despatched to von Kluge’s headquarters to ensure compliance with Hitler’s directive. von Kluge intimated that the proposed counter-offensive had no chance of success, and suggested that the German forces in Normandy should retire to the line of the Seine river, pivoting on the intact defences to the south of Caen, but on 4 August Hitler categorically ordered the German offensive to be launched, demanding that eight of the nine Panzer divisions in Normandy be used in the attack, and instructing the Luftwaffe to commit its entire reserve, including 1,000 fighters, in support. According to Hitler, the three conditions needed for the offensive to be successful were that von Kluge had to believe in it, had to be able to redeploy enough armour from the main front in Normandy to create an effective striking force, and must achieve surprise.

Although ordered to wait until the full strength required for the offensive had been assembled, von Kluge and Hausser, whose 7^th Army held the western part of the front, decided to attack as soon as possible and therefore before the Germans' overall situation deteriorated still further. As noted above, the primary formation assigned to the undertaking was von Funck’s XLVII Panzerkorps, and instead of the eight Panzer divisions demanded by Hitler, had only four (one of them incomplete) which could be relieved from their defensive tasks and assembled in time. These formations were Generalleutnant Heinrich Freiherr von Lüttwitz’s 2^nd Panzerdivision, Generalleutnant Gerhard Graf von Schwerin’s 116^th Panzerdivision, SS-Brigadeführer under Generalmajor der Waffen-SS Otto Baum’s 2^nd SS Panzerdivision 'Das Reich' and part of SS-Brigadeführer und Generalmajor der Waffen-SS Theodor Wisch’s 1^st SS Panzerdivision 'Leibstandarte Adolf Hitler', with a total of about 300 armoured fighting vehicles. The Panzer corps was supported by two infantry divisions and five Kampfgruppen, the latter formed from the remnants of Generalleutnant Fritz Bayerlein’s Panzer-Lehr-Division and four equally battered infantry divisions.

von Kluge ordered the start of the offensive for the night of 6/7 August without any preparatory artillery bombardment in order to avoid alerting the US forces to the attack. The intention was for the German formations to attack to the west from the line of the Sée and Sélune rivers toward Mortain and Avranches, and thus initially to hit Major General Leland S. Hobbs’s 30^th Division in the area to the east of Mortain and then smash through the US defences (another four US infantry divisions and three US armoured combat commands) to reach the coast. Had surprise been achieved, the attack might have fared better, but Allied decryption of German signals had made it possibly for the 'Ultra' system to provide warning of 'Lüttich' by 4 August and, as a result, Bradley was able to obtain air support from both Lieutenant General Lewis H. Brereton’s (from 8 August Major General Hoyt S. Vandenberg’s) 9^th AAF and Air Marshal Sir Arthur Coningham’s British 2^nd Tactical Air Force.

At 22.00 on 6 August, von Funck reported that his troops were still not concentrated, and the commander of the 116^th Panzerdivision 'had made a mess of things': in fact von Schwerin was so pessimistic about the operation that he had not even ordered his tank units to take part. The resulting delay disjointed the German attack, but on the German left the SS Panzer units fell on the positions of the 30^th Division to the east of Mortain shortly after 24.00. The Germans achieved tactical surprise as the 'Ultra' information about the imminent German attack had reached the headquarters of the 1^st Army too late for an immediate warning to be issued. The Germans took Mortain, although only temporarily, but were unable to breach the 30^th Division’s lines as the 2/120^th Infantry was holding Hill 314, the dominant feature around Mortain and, though cut off, was able to continue to hold this with the aid of parachuted supplies. However, of the 700 men who defended the position until 12 August, more than 300 were killed.

Farther to the north, the 2^nd Panzerdivision attacked several hours later on a south-westerly axis aimed at Avranches, and managed to penetrate several miles into the US lines before being halted by Major General Paul W. Baade’s 35^th Division and a combat command of Brigadier General Maurice Rose’s 3^rd Armored Division only 2 miles (3.2 km) from Avranches. The German high command ordered the attacks to be renewed during the morning, so that Avranches could be taken before the Americans could create an effective defence of the town, with the aid of SS-Obergruppenführer und General der Waffen-SS Wilhelm Bittrich’s II SS Panzerkorps (SS-Oberführer Friedrich-Wilhelm Bock’s 9^th SS Panzerdivision 'Hohenstaufen' and SS-Gruppenführer und Generalleutnant der Waffen-SS Heinz Harmel’s 10^th SS Panzerdivision 'Frundsberg') detached from General Heinrich Eberbach’s 5^th Panzerarmee, as the Panzergruppe 'West' had been redesignated on 5 August.

By 12.00 on 7 August the early morning fog had dispersed, and large numbers of Allied aircraft appeared over the battlefield. With the advance knowledge of the attack provided by the 'Ultra' system, the 9^th AAF had been reinforced by the 2^nd Tactical Air Force and, despite assurances by the Luftwaffe that the German forces would have adequate air support, the Allied aircraft quickly achieved complete air superiority over the Mortain area. The Luftwaffe reported that its fighters were engaged by Allied aircraft from the moment they took off, and were unable even to reach the battlefield. This meant that in the open area to the east of Mortain, the German armoured fighting vehicles became exposed targets, especially for the rocket-firing Hawker Typhoon fighter-bombers of the 2^nd Tactical Air Force.

Early accounts of the Allied fighter-bomber attacks in the Battle of Mortain accepted the claims of the pilots that more than 200 German tanks had been destroyed. Later detailed studies of the battlefield showed that most of the destroyed German armour was in fact knocked out by gunfire from ground forces and that the main effect of the Allied air attacks had been to destroy the unarmored vehicles and troops in the German offensive, as well as forcing the German armour to disperse to cover. The accuracy of the rockets and bombs of the Allied fighter-bombers was simply too poor to destroy more than a few of the German tanks, although fear of being incinerated inside a tank should a rocket or bomb actually strike a tank did cause some of the inexperienced German tank crews to abandon their tanks intact while under air attack.

Right through 7 August, US troops had continued to press on to the south near Vire, on the right flank of the German attack. Supposed to advance in this sector, the 116^th Panzerdivision was actually driven back. During the afternoon, the 1^st SS Panzerdivision and 116^th Panzerdivision made renewed attacks, but the flanks of the Mortain position had been sealed, allowing the VII Corps to contain the German advance.

Meanwhile, Bradley had despatched two armoured combat commands against the German southern flank. On 8 August, a combat command of Major General Edward H. Brooks’s 2^nd Armored Division was attacking the rear of the two SS Panzer divisions. Although fighting round Mortain continued for several more days, there was no further prospect of any German success. The Germans issued orders to go onto the defensive along the entire front, but poorly communicated orders resulted in this being impossible to achieve, with some German forces retreating, and others preparing to hold their ground.

As the 1^st Army counterattacked the German units near Mortain, units of the 3^rd Army were advancing unchecked through the open country to the south of the German forces, and had taken Le Mans on 8 August. On the same day, General H. D. G. Crerar’s Canadian 1^st Army attacked the weakened German positions south of Caen in 'Totalize' and threatened to break through to Falaise, although this attack stalled after two days. Hitler ordered the attacks against Mortain to be renewed with greater intensity, demanding that Generalmajor Erwin Jollasse’s 9^th Panzerdivision, almost the only formation opposing Patton’s advance farther to the east from Le Mans, be transferred to Mortain to take part in the attack. Eberbach was ordered to form a new headquarters, that of the so-called Panzergruppe 'Eberbach', to take command of the renewed offensive. Fearing that he was about to be implicated in the 20 July plot to assassinate Hitler, von Kluge acquiesced in this apparently suicidal order, but Eberbach’s proposed counterattack was soon overtaken by events and was never launched.

By 13 August, the 'Lüttich' offensive had come to a complete halt and the German forces had been expelled once more from Mortain. The Panzer divisions involved in the offensive had lost more than 150 of their tanks, which represented more than half of those committed, to Allied ground counterattacks and air attacks. As Hitler ordered the German forces in Normandy to hold their positions, the US VII and XV Corps were swinging to the east and north toward Argentan: the German attack in the west had left the 7^th Army and 5^th Panzerarmee in danger of being encircled by the Allied forces. As US forces advanced on Argentan, British and Canadian forces advanced on Falaise, threatening to cut off both armies in the newly formed Falaise pocket.

Although the US casualties in 'Lüttich' were significantly less than those in previous operations, in certain sectors of the front, notably the positions held by the 30^th Division around Mortain, there were severe casualties. By the end of 7 August alone, nearly 1,000 men of the 30^th Division had been killed. The estimates of US combat deaths in the period between 6 and 13 August vary from 2,000 to 3,000, with an unknown number of wounded.

On 14 August, Canadian forces launched 'Tractable' in conjunction with US movements to the north in the direction of Chambois. On 19 August, a brigade of Generał brygady Stanisław Maczek’s Polish 1^st Armoured Division linked with forces of Brigadier General Raymond S. McLain’s US 90^th Division, sealing some 50,000 German troops in the pocket. By 21 August, German attempts to reopen the gap had been thwarted, and all German troops still trapped in the pocket surrendered to the Allied forces, effectively terminating the existence of the 7^th Army in its current form.