- Theatre: North West Europe
- Dates: 7 to 11 August 1944
- Location: North West France
- Outcome: Partial Allied breakout to the south east.
- Allies: Lieutenant General Henry Crerar's Canadian 1st Army, comprising 1st (British) and 2nd (Canadian) Corps
- Axis: Field Marshal Günther von Kluge's Army Group B, including General Heinrich Eberbach's 5th Panzer Army and SS General Paul Hausser's 7th Army; German divisions including Hitler Youth 12th SS Panzer
As the US Cobra advance continued southwards from the coast into Brittany, Hitler ordered a counter-attack: Hausser's 7th Army was to strike westward, from Mortain in Brittany to the sea, cutting the US forces in two. Launched on 7 August, the attack ground to a halt within hours - given the balance of forces, it was little short of suicidal.
With the weakening and dispersal of German forces, Field Marshal Bernard Montgomery again began planning for a breakthrough towards Falaise, 32km (20 miles) south of Caen. The result was Operation Totalise, devised by Lieutenant General Guy Simonds of the Canadian 2nd Corps.
Simonds' innovation was a combined attack by armour and infantry: an armoured column of self propelled guns, or 'Priests', included several vehicles with the gun removed ('defrocked Priests'), each carrying 11 infantrymen. Launched on the night of 7 August 1944, the Totalise advance cut a swathe through German defences. Kluge, who had overruled Hausser and transferred 7th Army units from Brittany to the Mortain offensive, now sought Hitler's permission to transfer a unit from Mortain to Falaise. It was not granted.
On 9 August the Canadians came up against the young zealots of 12th SS Panzer, who showed their faith in Hitler - who had ordered all units to fight to the death - by fighting on when outnumbered 20 to one. However, there was no breakthrough; Totalise halted eight kilometres (five miles) outside Falaise. But with British and Canadian forces to the north and US forces to the south, Kluge's armies were now in grave danger.