<P> The initial Canadian attack on the town was made on 20 December by Canadian 2nd Brigade's Loyal Edmonton Regiment with elements of the Seaforth Highlanders of Canada under command . Meanwhile, elements of the division's 3rd Infantry Brigade launched a northerly attack to the west of the town in attempt to outflank and cut off the town's rear communications but made slow progress because of the difficult terrain and the skillful and determined German defence . </P> <P> The Germans also concealed various machine guns and anti-tank emplacements throughout the town, making movement by armour and infantry increasingly difficult . The house - to - house fighting was vicious and the Canadians made use of a new tactic: "mouse - holing". This tactic involved using weapons such as the PIAT (or even cumbersome anti-tank guns) to breach the walls of a building, as houses within Ortona shared adjoining walls . The soldiers would then throw in grenades and assault through the mouse holes, clearing the top floors and making their way down, where both adversaries struggled in repeated close - quarters combat . Mouse - holing was also used to pierce through walls into adjoining rooms, sometimes catching enemy troops by surprise . The tactic would be used repeatedly as assaulting through the streets caused heavy casualties for both Canadian and German troops . Throughout the battle, engineers on both sides used the brutal but effective tactic of using demolition charges to collapse entire buildings on top of enemy troops . After six days of combat, 2nd Brigade's third battalion, Princess Patricia's Canadian Light Infantry, joined the battle together with tanks from 1st Canadian Armoured Brigade's Three Rivers Regiment . </P> <P> On 28 December, after eight days of fighting, the depleted German troops finally withdrew from the town . The Canadians suffered 1,375 dead during the Moro River battles of which Ortona was a part . This represented almost a quarter of all Canadians killed during the entire Italian Campaign . </P> <Ul> <Li> <P> Infantrymen of the Loyal Edmonton Regiment advance with Sherman tanks of the Three Rivers Regiment </P> </Li> <Li> <P> Canadian rifleman, December 1943, Ortona, Italy . </P> </Li> <Li> <P> German corporal killed during fighting against the Loyal Edmonton Regiment, Ortona, Italy . </P> </Li> <Li> <P> Ortona War Cemetery, which contains 1,615 dead. 1,375 of whom are Canadian, 169 British, 42 New Zealanders, 16 South Africans, 5 Indian, 4 Australian, 2 other allied . 52 are unidentified by name and 2 are entirely unidentified . </P> </Li> </Ul>

How long did the battle of ortona last