Ushering in the second half of April was another Communist attack, this one on 15–16 April and to be the last that month against the central part of the Marine Division sector. This attempt to breach the Marine lines was directed against Company E of 2/5, manning an outpost position on the OPLR. The rest of the battalion was now holding the left sector of the center regimental front, having assumed its new mission on line three days earlier in relief of 1/5, which reverted to the role of regimental reserve. Northwest of the 5th Marines MLR, the Company E commander, Captain Charles C. Matthews, had placed a reinforced rifle platoon. His Marines had occupied several dug-in positions near the top of a 400-foot hill, known as Outpost 3 (OP 3). (See Map 5.) The platoon had been improving this outpost area and fortifications so that the bunkers could be employed for living and fighting.[45] During the afternoon and again at dusk on 15 April the Communists had shelled this location. One Marine was wounded in the second firing. [45] Chapter III discusses in detail the construction of bunkers. [Illustration: MAP 5 K. WHITE 2/5 SECTOR 15–16 APRIL 1952] At 2330 on 15 April, Company E reported that a green flare cluster had just burst over Hill 67, approximately 1,900 yards southwest of OP 3 and just beyond the OPLR. This signal triggered a 20-minute heavy enemy preparation of 76mm artillery and 120mm mortars on the friendly outpost and its supporting mortar position. Ten minutes before midnight, another green flare exploded over the same height, and the shelling stopped. After five minutes the signal reappeared. Immediately thereafter, the Chinese shifted their artillery and mortar fire to an area west of the OP 3 mortar site and north of a Company F observation post. At the same time, the enemy attacked Outpost 3. Initially, the Chinese struck the Marine defenses in a frontal assault, but as the fighting progressed enemy forces quickly enveloped the outpost and charged it simultaneously from three sides. The vastly outnumbered Marine defenders withdrew into a tight perimeter at the southeastern corner of the outpost where their defending firepower prevented the enemy from seizing the position. Within 15 minutes the enemy had surrounded the Marines and severed the outpost communications, but could not take the outpost. The CCF soldiers then pulled back and let their artillery soften OP 3 while they regrouped for another assault. The Chinese soon stormed the outpost a second time, but were again unsuccessful. Moreover, they lost three of their men who were captured by the tenacious 2/5 defenders.