A mine explosion that killed many German troops of Reserve Infantry Regiment 262 manning the front line, preceded the advance of the 3rd Canadian Division. The remaining German troops could do no more than man temporary lines of resistance until later manning a full defence at the German third line. As a result, the southern section of the 3rd Canadian Division was able to reach the Red Line at the western edge of the Bois de la Folie at around 7:30 am. At 9:00 am the division learned of its exposed left flank, as the 4th Canadian Division had not yet captured Hill 145. The 3rd Canadian Division was thus called upon to establish a divisional defensive flank to its north. Although the German commanders were able to maintain open lines of communication and issue orders, even with swift staff work the tempo of the assault was such that German decision cycle was unable to react decisively.