At midnight, the Union guns opened fire on the Confederate fortifications. Around 4:00 A.M., both 9 and 6 corps advanced with "pioneers" in the lead. The "pioneers" job was to hack through the wooden defenses that formed the first Confederate line. The pioneers were followed by Infantry with fixed bayonets. The 9 corps got to "Fort Damnation" where they gained partial possession of the fort bet the Confederates rallied back and began pushing the Union back. The 6 corps had better luck and they pounded the Confederate line. By shortly after 5:00 a.m., the Confederate line was completely smashed, and the defenders were fleeing in all directions.