Even with 2/26 in position, there was still a flaw in the northern screen. The line of sight between K/3/26, on Hill 861, and 2/26 was masked by a ridgeline which extended from the summit of 861 to the northeast. This stretch of high ground prevented the two units from supporting each other by fire and created a corridor through which the North Vietnamese could maneuver to flank either Marine outpost. About a week after his arrival on Hill 558, Captain Earle G. Breeding was ordered to take his company, E/2/26, and occupy the finger at a point approximately 400-500 meters northeast of K/3/26. From this new vantage point, dubbed Hill 861A, Company E blocked the ridgeline and was in a good position to protect the flank of 2/26. Because of its proximity to K/3/26, Company E, 2/26, was later transferred to the operational control of the 3d Battalion. Although these units did not form one continuous defensive line, they did occupy the key terrain which overlooked the valley floor.(40) With the primary avenue of approach blocked, Colonel Lownds utilized his remaining assets to provide base security and conduct an occasional search and destroy mission. The 1st Battalion was given the lion's share of the perimeter to defend with lines that extended around three sides of the airstrip. Lieutenant Colonel Wilkinson's Marines occupied positions that paralleled the runway to the north (Blue Sector), crossed the eastern end of the strip, and continued back to the west along the southern boundary of the base (Grey Sector). The southwestern portion of the compound was manned by Forward Operating Base-3 (FOB-3), a conglomeration of indigenous personnel and American advisors under the direct control of a U. S. Army Special Forces commander. FOB-3 tied in with 1/26 on the east and L/3/26 on the west. Company L, 3/26, was responsible for the northwestern section (Red Sector) of the base and was thinly spread over approximately 3,000 meters of perimeter. The remaining company from the 3d Battalion, M/3/26, was held in reserve until 19 January when two platoons and a command group were helilifted to 881S. Even though it held a portion of the perimeter, Company D, 1/26 became the reserve and the remaining platoon from M/3/26 also remained at the base as a reaction force.[13](41)