It appeared for a few hours on 21 September that the enemy might be planning to retake Kimpo Airfield. At 0730 a report came to the 3d Battalion, KMC Regiment, warning of an attempted NKPA crossing of the Han in the area about seven miles northwest of the field. Air strikes were called immediately with the result of dispersing the enemy. At 1310, however, an estimated two NKPA battalions were reported in front of KMC positions by the air liaison officer attached to the battalion. All units in the Kimpo area were alerted to the possibility of attack. The CO of the 1st Shore Party Battalion was designated as coordinator of defensive forces consisting of his unit, and elements of the 1st Engineer Battalion, 1st Tank Battalion, 1st Ordnance Battalion, and 1st Amphibian Tractor Battalion. Army troops of the 56th Amphibian Tractor Battalion were also ordered to Kimpo.
With an NKPA attack threatening, some concern was felt about an enemy Yak type aircraft—fueled, armed, and ready for flight—which had been discovered in a revetment on the edge of the airfield by First Lieutenant Edward E. Collins of the Ordnance Battalion and later of the 5th Marines. The plane was hastily disarmed and painted with U. S. markings, so that it could be flown to Japan in case the enemy overran Kimpo.[313]
[313] Capt E. E. Collins ltr to authors, 6 May 55.
Although the NKPA threat did not materialize, there could be no doubt of an enemy build-up within striking distance. And it was on this sensitive left flank that the support of naval gunfire was most effective.
As early as 19 September the 1st and 5th Marines had advanced beyond the range of the light cruisers and destroyers. The battleship Missouri was made available the next day, but targets in Seoul proved to be too distant for her maximum range, and no further efforts were made to call upon the battleship’s 16-inch rifles. In the Kimpo area, however, naval gunfire was at its best, and a total of 535 8-inch shells were fired from 21 to 24 September by the Toledo and Rochester. These fires were requested by Lieutenant Wayerski in support of patrol actions by the 3d KMC Battalion. One of the KMC attacks wiped out a company-size pocket of Red Korean resistance in the vicinity of Chongdong—about three miles northwest of the airfield on the south bank of the Han—with a loss to the enemy of 40 counted dead and some 150 prisoners.[314]
[314] Capt J. R. Wayerski, interv, of 28 Sep 54.
After the Han crossing, the 1st Marine Division found itself in the position of advancing astride an unbridged tidal river with the northern flank wide open. Generals Smith and Craig depended on VMO-6 helicopters for their visits to the 5th Marines front. Those rotary-winged aircraft were in increasing demand for evacuating serious casualties; and the commanding general directed that such missions be given priority over command and liaison flights. This meant that Smith and Craig were occasionally “bumped.” In such instances they crossed the river by LVT or waited until their helicopter could return.
At the time of the Han crossing, the general plan of the 1st Marine Division had been for RCT-5 to clear the north bank and open up crossing sites for RCT-1 in the Yongdungpo area. That regiment would then cross to seize South Mountain, just north of the crossing site, thus forming an enclave in Seoul proper. Further objectives were to be seized by RCT-1 to the north and east while the KMC Regiment passed through RCT-5 to attack the center of the city. Here a political motive entered the picture, since it was desired to have Koreans take a prominent part in the liberation of the former ROK capital. To the north, on the left flank of the Division, it was planned for RCT-7 to seize objectives to protect the flank and cut off the escape of the enemy. Meanwhile, RCT-5 would revert to Division reserve as soon as the tactical situation made it possible.
So much for the plan. Before it could be put into execution, stiffening NKPA resistance made it necessary to consider revisions.[315] Not only was the hilly terrain northwest of Seoul well suited to defensive operations, but it had been a training area as far back as the Japanese overlordship, with fields of fire accurately charted. Moreover, it had become evident by the 21st that the enemy was about to exchange a strategy of delaying operations for one of defending to the last ditch. The 1st Marines had already experienced the new NKPA spirit at Yongdungpo, and on the 21st the 5th Marines contented itself with limited advances for the purpose of seizing high ground from which to launch the assault on Seoul.
[315] O. P. Smith, Notes, 253–255.