The statistics of the 1st MAW indicate that out of a total of 1,875 combat sorties flown from 1 to 15 June 1951, about a third were close air support--651 day CAS and 19 night CAS. Of this number, 377 sorties went to the 1st Marine Division, which received more than half. Next in line were the 7th Infantry Division (41 sorties), the 3d Infantry Division (31 sorties), and the 25th Infantry Division (28 sorties).[229] [229] 1st MAW _HD_, Jun 51. Pt 1, Chronology, 15 Jun. The effect of Operation STRANGLE on the enemy must be left largely to conjecture. There can be no doubt that it added enormously to the Communists’ logistical problem. It is equally certain that they solved these problems to such an extent that their combat units were never at a decisive handicap for lack of ammunition and other supplies. Operation STRANGLE, in short, merely added to the evidence that interdictory air alone was not enough to knock a determined adversary out of the war, as enthusiasts had predicted at the outbreak of hostilities in Korea. _KMC Regiment Launches Night Attack_ On the night of 1–2 June, Colonel Nickerson was notified that the 7th Marines would be relieved next day by the 1st Marines, which would pass through and continue the attack. The 1st Marines moved into assembly areas at 0630. Lieutenant Colonel Homer E. Hire, commanding officer of 3/1, went forward at 0800 with his command group to make a reconnaissance of the area. As his staff paused for a conference in a supposedly enfiladed location, a Communist mortar barrage hit the group by complete surprise. The artillery Liaison officer was killed instantly. His assistant, two forward observers, four company commanders, the S-3 and 32 enlisted men were wounded. So hard hit was the battalion that its attack had to be postponed until the following day.[230] [230] CO 1stMar msg to CG 1stMarDiv, 1915 2 Jun 51. The first Division objective was designated X-RAY. 2/1 had the mission of taking the high point, Hill 516 (Map 15). Across the valley 3/1 advanced up a parallel ridge. Planes from VMF-214 and VMF-323 cleared the way for the securing of this battalion’s objective at 1900. Aircraft from these same squadrons also aided 2/1 in over-running the last opposition on Hill 516, where 80 NKPA dead were counted.[231] [231] CO 1stMar msg to CG 1stMarDiv, 1830 3 Jun 51; _HD_s of VMF-214 and VMF-323, Jun 51. [Illustration: MAP 16 1st MARINE AIR WING OPERATING AREA 23 MAY-15 JULY 1951 UNIT LOCATIONS ON 1 JULY] The KMC regiment, in reserve only two days, was ordered to relieve the 5th Marines on 4 June. This would permit Colonel Hayward to shift over to the right flank, thus extending the 1st Marine Division zone 5,000 yards to the east with a north-south boundary of the Soyang river valley (Map 15). The purpose of this maneuver was to free 2d Infantry Division troops for a mission of mopping up in the X Corps rear area.