'Cannonshot' was the Canadian attack by Major General H. W. Foster’s 1^st Division of Lieutenant General C. Foulkes’s I Corps in General H. D. G. Crerar’s 1^st Army across the IJssel river near Deventer in the Netherlands as the first stage in the 'Quick Anger' liberation of Arnhem (10/11 April 1945).

The bridgehead of Field Marshal Sir Bernard Montgomery’s Allied 21^st Army Group, secured in 'Plunder', did not include the town of Emmerich on the right bank of the Rhine just inside Germany, but the full strength of the Canadian 1^st Army could not be deployed without the use of another bridge over the Rhine at this point. Montgomery and Crerar had therefore decided to capture the town from the bridgehead, and this was achieved after a three-day battle.

The Rhine had been bridged at Emmerich by midnight on 1 April. Even before the Emmerich bridge had been opened to traffic, Lieutenant General G. G. Simonds’s Canadian II Corps had already put its three Canadian divisions across the Rhine by means of the bridges farther upstream at Rees. The first bridge at Emmerich was quickly supplemented by another two, and on 2 April the Canadian II Corps' leading troops had reached the Twente Canal and, after gaining bridgeheads across this against the opposition of Generalleutnant Hermann Plocher’s 6^th Fallschirmjägerdivision of General Felix Schwalbe’s LXXXVIII Corps in General Günther Blumentritt’s 25^th Army within Generaloberst Johannes Blaskowitz’s Heeresgruppe 'H', had broken out in the north on 4 April with Major General C. Vokes’s Canadian 4^th Armoured Division on the right and Major General A. B. Matthews’s Canadian 2^nd Division in the centre, while Major General H. R. Keefler’s Canadian 3^rd Division on the left cleared the western flank in the direction of the IJssel river.

The country in the north was crossed by many streams, rivers and canals but inhabited by a friendly Dutch population, and it was decided to drop small parties of Special Air Service troops in the area in order to confuse the Germans while seizing and holding bridges and airfields for the following Canadians. The SAS troopers were to be assisted by reconnaissance vehicles and Belgian SAS jeeps operating ahead of the Canadians.

On the night of 7 April, 47 Short Stirling transport and tug aircraft of the RAF’s No. 38 Group dropped nearly 700 men of the 2^nd and 3^rd Régiments de Chasseurs Parachutistes in 'Keystone'. In the main this SAS force achieved its objectives, took 200 prisoners and caused many German casualties at the cost of 90 of their own men: a few of the parties held their objectives for a week before they were relieved. But the Canadian attack now made fast progress. The Ems river estuary near the German border was reached by Major General S. Maczek’s Polish 1^st Armoured Division on 18 April, Groningen was captured and cleared by the Canadians on 16 April after four days of street fighting, and on the eastern bank of the IJssel river the Canadians captured Zutphen on 8 April after a stiff fight and Deventer with strong air support on 10 April, and Zwolle was finally cleared without difficulty.

The Canadians then advanced swiftly on Leeuwarden, 70 miles (115 km) to the north, and occupied the town on 18 April. Pockets of German resistance in the surrounding country were mopped up, and by 19 April the only part of the northern Netherlands remaining in German hands was an area to the west and south of Delfzijl on the Ems river estuary.