 On 11 April, the 4th Guards Infantry Division first reinforced and then relieved affected 16th Bavarian Infantry Division units.The night before the attack, artillery harassed German positions while a gas section of Royal Engineers, employing Livens Projectors, fired more than 40 drums of gas directly into the village of Givenchy-en-Gohelle to cause confusion.The defending German troops managed to drive back the initial Canadian assaults at around 4