Fortunately for the attackers, a parallel valley enabled a platoon of tanks from Baker Company, 1st Tank Battalion, to knock out unusually strong CCF bunkers with direct 90mm fire while Fox Company riflemen followed along the ridgeline with a grenade attack before the enemy had time to recover. Thanks to intelligent planning, not a single Marine was killed or wounded as the battalion dug in for the night on Hill 330. Adopting the same tactics on the 20th, after artillery preparation and an air strike by VMF-214 and VMF-323 planes, Easy Company of 2/1 advanced along the ridgeline connecting Hills 330 and 381 while tanks moved forward on either side providing direct flat-trajectory 90mm fire. By 1315 the Marines had overrun the enemy’s main line of resistance without a casualty.[141] [141] 1stMarDiv _HD_, Mar 51, 10; VMF-214 and VMF-323 _HD_, Mar 51. _1st KMC Regiment Returns to Division_ As the Eighth Army jumped off on 20 March from Line BUFFALO toward Line CAIRO (Map 9), the 1st KMC Regiment was attached again to the 1st Marine Division. This was the third time that Lieutenant Colonel Charles W. Harrison had been directed to reorganize and reassemble a KMC liaison advisory group. The 3d Battalion of the 11th Marines, commanded by Lieutenant Colonel William McReynolds, was placed in direct artillery support. When the advance was resumed, the KMCs attacked between the 1st Marines on the right and the 5th Marines on the left.[142] [142] Col C. W. Harrison, _Narrative_, Mar-Apr 51, 2–3. The high _esprit de corps_ of the KMCs shines forth from a comment written in his own English by First Lieutenant Kim Sik Tong: “The KMC ideal is to complete the mission, regardless of receiving strong enemy resistance, with endurance and strong united power, and always bearing in one’s mind the distinction between honor and dishonor.”[143] [143] 1stKMCRegt _POR_, 24 Mar 51. The zone of the KMC Regiment was a roadless wilderness, making it necessary to air-drop ammunition and supplies for the attack on Hill 975. This was the hardest fight of the Division advance to Line CAIRO. Excellent artillery support was provided for the 2d and 3d Battalions as they inched their way forward in three days of bitter combat. Not until the morning of 24 March was the issue decided by maneuver when the 1st Battalion moved around the left KMC flank into a position threatening the enemy’s right. Resistance slackened immediately on Hill 975 and the KMCs took their objective without further trouble. The 1st and 5th Marines were already on Line CAIRO, having met comparatively light opposition from NKPA troops who had relieved the 66th and 39th CCF Armies. Apparently the enemy was using North Koreans as expendable delaying elements while massing in the rear for an offensive that could be expected at any time. A smoke screen, produced by burning green wood, shrouded the front in an almost constant haze.