[188] Ibid.
It was its opposite of the 1st Marines that Dog Company of 2/5 met at Hill 117. Fox Company of 2/1 had been clearing the eastern reaches of the big ridge since 0615, and Easy was to spend all morning and afternoon securing high ground and a village about a mile off on the right flank. When the attack along the highway resumed shortly after 0900, Company D of the 5th Marines and a platoon of A/Tanks took the lead. Fox and Dog Companies of 2/1 followed in trace and on the right as the formation advanced rapidly against nothing heavier than sniper fire. By 1100, elements of both battalions were deployed at Sogam-ni, just a few hundred yards short of smoking Kansong-ni. Since the former hamlet bordered the O-3 Line, the Marines held up to await further orders.[189]
[189] Ibid.; 2/1 SAR, 4; Cunliffe interv, 24 Aug 54; LtGen E. A. Craig ltr to CMC, 21 Apr 55; and Capt J. L. Carter ltr to CMC, 19 Apr 55.
To the south of the highway, the 1st Battalion, 1st Marines, reorganized in the center of Puller’s zone and moved forward as regimental reserve. Simultaneously, the 3d Battalion began its sweep of the Munhang Peninsula, Companies G and I attacking generally southward from Hill 233. Since the broad front was studded with high ground and villages, Lieutenant Colonel Ridge relied on LVT transport whenever possible to regain momentum lost to hill-climbing and searching. Resistance on the peninsula proved negligible, although once again the capture of prisoners and materiel revealed enemy potential unused. Among the weapons abandoned by the North Koreans were quantities of rifles and machine guns, a battery of Russian-made 120mm mortars, and four coastal guns, the latter pointing menacingly toward the ships of the Attack Force anchored in the channel.[190]
[190] 3/1 SAR; Crowley-Adams interv, 9 Feb 55; Col T. L. Ridge ltr to CMC, 12 May 55; LtCol J. Hawkins ltr to CMC, 27 Apr 55; and LtCol E. H. Simmons ltr to CMC, 15 Apr 55.
Although 1/1 and 3/1 did not reach their portion of the objective until later in the day, Division Headquarters realized by midmorning that enemy resistance as far out as the O-3 Line could be discounted. Now that the tremendous obstacles of the actual landing had been overcome, the tactical advantage of the moment swung from the Red commander at Seoul to General Smith. Owing to the conformation of the Inchon and Munhang Peninsulas, which were linked together inland like Siamese twins, the O-3 Line formed a front three miles long with both flanks bounded by water. A glance at the map will show the beachhead thus set off as an ideal foothold. To North Koreans thinking in terms of counterattack, the vacuum rapidly being filled by the Landing Force was a defensible bottleneck. To the Marines, on the other hand, it was the gateway to freedom of maneuver for an overland offensive.
Advance to the Force Beachhead Line
Opening the gate was the subject of General Smith’s OpnO 4-50, issued by dispatch at 1045, D-plus 1. He directed Puller and Murray to continue the attack from the O-3 Line, seized the Force Beachhead Line (FBHL), and thereby conclude the assault phase of the amphibious operation. The order also marked off a new Tactical Bomb Line,[191] behind which Marine Air was forbidden to strike without ground coordination.
[191] The first bomb line corresponded to the FBHL, and Corps Phase Line AA was the equivalent of the O-2 Line.
Roughly the shape of a right angle, the FBHL corresponded to X Corps Phase Line BB. Like the O-3 arc, it was anchored on the sea at both ends. The east-west leg of the angle, five miles long, lay above and almost parallel to the Inchon-Seoul Highway. The north-south leg, about seven miles inland, added a third projection, the Namdong Peninsula, to the beachhead. Encompassing the built-up centers of Ascom City and Mahang-ri on the main road, the apex of the FBHL pointed northeast toward Kimpo Airfield like an arrowhead.