On why the enemy was reluctant to give up ground, and probably why he decided
to return to negotiating (since he was not succeeding in repulsing UN attacks and was
losing ground) a EUSAK report speculated:
When the enemy reached the 380 Parallel, he could not afford to "lose
face" by sacrificing territory of the homeland of the North Korean people. To do
so, he may have felt, would cause loss of respect of the North Korean people
and possibly of the entire oriental world.
In view of a possible armistice, to permit sections of North Korea to fall
into United Nations hands would have given UN delegates a weapon in
negotiation. Furthermore, forcing the UN troops to halt at the 380 Parallel would
have enabled the Communist world to retain its "iron curtain" in Korea.
Probably the most logical reason for the change to stubborn defense
tactics [as opposed to trading space for time] was.., because of friendly air and
artillery, [he had to resort] to attempts to annihilate small friendly units [as
opposed to isolating and destroying larger ones]. This tactic was more effective
when the MLR in defense was employed. .. .34
UN forces used the following basic process as SOP to overcome enemy defenses:
In a typical assault on an enemy defensive position, air and artillery were
first used in the softening up process. Aerial bombs weighing 250 and 500
pounds, with a 10-second delay nose and tail fusing, proved effective on enemy
fortifications provided a direct hit was scored. Aerial bombardment was restricted
due to the lack of required precision bombing [or CAS, which could actually
achieve a precision hit as opposed to the area "precision" of the AF]. On an
average, one bunker was destroyed out of eight bomb drops on positively
identified targets. This average decreased in adverse weather or because of poor
target identification. Field commanders felt that three fighter-bombers, utilizing
250-pound bombs was required for each bunker.
... [Concerning artillery] it was proven that a direct hit by a 155mm shell
was effective on enemy pillbox with 5-foot protective roof; a direct hit with 105mm
shell was effective on one with a 3-foot protective roof. The best artillery support
was provided by the direct fire of a 155mm gun, although high angle fire from
heavy artillery also proved effective....
When artillery fire was lifted, 4.2mm and 82mm mortars pounded the
enemy positions at three-minute intervals as the assaulting force moved up.
Tanks moved forward of the infantry in the final assault and tried to close within a
range less than 1000 yards to fire on the enemy bunkers. A range of 300 to 400
yards was preferred ... .35
34 Ibid., 88.
35 Headquarters EUSAK, "Enemy Tactics," 108.
Montandon, Joshua W. Battle for the Punchbowl: The U. S. 1st Marine Division 1951 Fall Offensive of the Korean War. Denton, Texas. UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc3938/. Accessed June 26, 2016.