One technique the Marines employed in the Bunker Hill battle was defense of the reverse (protected) side of the hill. Although counter to the usual American military practice, the reverse slope defense was required by the intense artillery and mortar fire massed upon the front slope defenders. As the 3/1 battalion commander later commented:
It’s true, we suffered from the heavy incoming—but had we had to work replacements, casualties, and supplies all the way up to the (forward) military crest of Bunker—the losses would have been prohibitive. With the weight of the incoming and our inability to get greater infantry mass onto the battlefield at one time, a conventional defense would have been far more costly ... [after] the damage done to Baker Company in the [12 August] afternoon attack ... had we not gone into a reverse slope defense, we could not [have held] with the strength at hand.[203]
[203] Armitage ltr and draft MS comments, p. 7. For further details of the Bunker Hill action, see Armitage ltr in v. V, Korean comment file.
On the other hand, a tactical weakness of the reverse slope defense, that “plagued us until the end of the battle,”[204] was the fact that the 1st Marines initial gain was not more fully exploited. As the battalion commander explained:
[204] Ibid., p. 8.
To be successful, in a reverse slope defense, the defender must immediately counterattack, retake and reoccupy the forward slope of the position as soon as enemy pressure diminishes. Because of the incoming and primarily because of our overextension in regiment, we ... [employed] piecemeal commitment ... and fed units into the battle by company, where we should have employed our entire battalion in counterattacks to punish the withdrawing force and restore the forward slope. To the very end, lack of decisive strength prevented this. We stayed on the reverse slope all the way, except for brief forays to the forward slope.[205]
[205] Ibid.
Some officers felt, in retrospect, that a more feasible solution during the August battle might have been to move all three battalions on line—3/1, 1/1, and 2/1, with the reserve battalion (1/1) deployed on a narrow front. This would have provided decisive strength on Bunker and the MLR behind it to give greater depth counterattack capability, and better control at the point where needed.[206] Departure from standard doctrine by employment of the reverse slope defense furthered the existing controversy as to the best method of ground organization in the division sector. But it was to be some months before a change would be effected.[207]
[206] Ibid., p. 9.
[207] As the military situation changed in Korea to become increasingly one of a battle of position and attrition, the Marine Corps Basic School, Quantico, Va. curriculum was revised to give greater emphasis to tactics of positional warfare. Close attention was paid to terrain evaluation, employment of infantry units, offensive and defensive use of automatic and supporting weapons, night counterattacks, field problems of reverse slope defense, and even tasks of “research into WW I—and the American Civil and Revolutionary Wars for the tactic of Reverse Slope defense.” Armitage ltr.