As the 1st Marine Division drew back to the curving Pendleton line at the right of the IX Corps sector on 23 April, Marine aerial reconnaissance disclosed numerous enemy groups moving south through the ground surrendered by the ROK 6th Division the night before. They appeared to be van forces moving well ahead of main bodies, though the latter were not sighted. The Marine intelligence staff concluded that the groups nearest the marines were attempting to get into position for a strike against the division's main supply route.1
If this was the case, the 120th Division, 40th Army, which had missed the opportunity to enter the marines' open left flank the previous night, also failed to find the open path to Ch'unch'on. In a shallower southeastward swing out of the ground along the division boundary, begun about 2000, the division's 359th and 360th Regiments launched repeated frontal assaults behind mortar fire against two battalions of the 1st Marines and a battalion of the 7th Marines now covering the division's left. The Chinese made no earnest effort to move through the gaps between battalions, a mistake that allowed the marines to concentrate defensive fires; the supporting fire delivered by the 11th Marines and Army artillery from Chich'on-ni was particularly effective. The Chinese kept heavy pressure on the three battalions all night but could deliver no penetrating blow. Frequent but far weaker attacks in other sectors of the Marine front by forces of the 115th and 116th Divisions of the 39th Army faded out at dawn.2
Starting the division's withdrawal to line Kansas about daylight, General Smith held to three engaged battalions and supporting artillery in position to contain the attack from the west and cover the units to the east as they vacated their inactive sectors. The artillery was to follow, with displacing units spaced to insure continuous support of the three battalions bringing up the rear. Smith's air officer requested twelve planes an hour to help cover the rearguard action.3
