By nightfall on the 31st the 7th Marines had control of Yanggu, its airfield, and the hills surrounding that burnt-out town. The 5th Marines had reached a point 6,000 yards northeast of Yanggu, astride the north-south ridgeline between that road center and Inje.
Losses for the 1st Marine Division in May added up to 75 KIA, 8 DOW, and 731 WIA. The ratio of wounded to killed, it may be noted, is more than nine-to-one. This proportion, so much more favorable than the usual ratio, rose to an even more astonishing 15-to-1 in June. Various explanations have been offered, one of them being the spirit of cool professionalism of Marines who had learned how to take cover and not expose themselves to needless risks. But this doesn’t account for the unusual ratio, and it may perhaps be concluded that the Marines were simply lucky in this operation.
The comparatively low death rate has also been credited in part to the alertness with which Marine officers adapted to changing situations. War is a grim business on the whole, but Colonel Wilburt S. Brown took an amusing advantage of enemy propaganda accusing Americans of all manner of crimes against humanity. At the outset he had requested colored smoke shells for signaling. But upon learning from POW interrogations that NKPA soldiers were terrified by what they believed to be frightful new gases, the commanding officer of the 1st Marines had an added reason for using green, red, and yellow smoke. Unfortunately, Lieutenant Colonel Merritt Adelman, commanding officer of the 2d Battalion, 11th Marines, soon had to inform him that the inadequate supply was exhausted.[213] It was never renewed during Brown’s command.
[213] MajGen W. S. Brown, USMC (Ret.), ltr of 21 Aug 58.
Major David W. McFarland, commanding officer of VMO-6, also exploited enemy ignorance. His original purpose in initiating night aerial observation by OY planes was to improve artillery accuracy. Soon he noticed that the mere presence of an OY overhead would silence enemy artillery.
“The aerial observer,” McFarland explained, “was often unable to determine the location of enemy artillery even though he could see it firing, because he would be unable to locate map coordinates in the dark—that is, relating them to the ground. Fortunately, this fact was unknown to the enemy. From their observation of the OYs in the daytime, they had found that the safest thing to do whenever an OY was overhead was to take cover. This they continued to do at night.”[214]
[214] LtCol D. W. McFarland, ltr of 21 Aug 58.
VMO-6 also put into effect an improvement of 1st Marine Division aerial photographic service at a time when the 1st MAW photo section had missions all over the Korean front. Lieutenant Colonel Donald S. Bush, commanding officer of the section, is credited with the innovation of mounting a K-17 camera on a OY. Only a 6-inch focal length lens could be installed on one of these small planes. This meant that in order to get the same picture as a jet the OY must fly at half the altitude. The pilot would be in more danger but haze problems were reduced.
The experiment was an immediate success. The Division set up a photo laboratory near the VMO-6 CP for rapid processing and printing. A helicopter stood by for rapid delivery to the units concerned.[215]
[215] Ibid.