A pair of North Korean vehicles (T-34/85, SU-76) in
Seoul, probably knocked out during the initial North Korean nighttime
counterattack on the 1st Marines when the Marines first entered the city.
Operations in Korea—United Nations Offensive. The
Department of History, United States Military Academy at West Point.
Mobility and Counter-Mobility
Although counter-mobility was central to the NKPA’s strategy
in Seoul, and the 1st Marine Division described “a most skillful delaying
action,” the Marines proved capable of pressing the advance. Even before US
forces entered the city, the North Koreans had recovered from their initial
surprise at the Inchon landings, relying on mines to slow the American advance.
The 1st Marines and their supporting armor encountered large minefields along
the Inchon-Seoul highway, which damaged or destroyed several vehicles. However,
these minefields were sometimes not well camouflaged or covered by fire.
That changed inside the city, where the NKPA combined mines
with barricades, and kept both nearby and under the observation of infantry,
crew-served weapons, artillery, and tanks. The barricades were mainly composed
of earth-filled rice bags, spanned the full width of the street, were
approximately ten feet high and five feet thick, and emplaced at every major
intersection (200–400 yards). Covering forces were usually waiting in adjacent
buildings or on nearby rooftops. Any approach by US forces sparked heavy fire
from small arms and crew-served weapons. While the main roads in Seoul were
wide, paved, and straight, the secondary roads were not. The North Korean focus
on the major roads was prudent as many of the secondary roads were also dead
ends. Some of the US troops tried exploring the secondary roads and found them
too narrow for their vehicles. Even on the main roads, debris and downed power
and telephone lines made travel difficult, causing many flat tires.
These mutually reinforcing elements at each defensive
position required US forces to carefully combine many elements of their own
capabilities to continue the advance. The infantry-armor-engineer team had to
work well together to keep US losses low and maintain the pace of advance.
Tanks would move forward and suppress the NKPA fire in the area, so that the
engineers could advance and clear the mines. Aircraft contributed by strafing
and rocketing. Mines were especially difficult to deal with inside the city
because they were harder to find in the rubble and debris in the streets. The
infantry would cover the armor, so NKPA infantry could not exploit the limited
visibility of the buttoned-up tank crews and charge forward with satchel
charges. Once the mines were cleared, the armor would blast holes in the
barricades and charge through (some with dozer blades), while continuing to
engage enemy forces behind the barricade. Some of the infantry would continue
to cover the tanks; others would then clear the nearby buildings and rooftops.
US troops repeated this process over and over, the average barricade taking
forty-five minutes to clear. Sometimes it took longer, and sometimes tanks were
knocked out by mines, but progress was steady. Despite the advantages afforded
a defender in urban terrain, and the NKPA focus on counter-mobility, the Marine
advance across the city still sometimes exceeded 2000 yards in a day.
While Marine Corps doctrine on urban warfare did not
specifically prescribe these methods to clear barricades, they were in line
with the spirit of the doctrine. The Marine Corps’ manual on urban warfare
mentioned the utility of “obstacles” for defensive urban warfare and the
section on street fighting in the Marine Corps’ manual for rifle squads was
immediately followed by a section on attacking fortified areas, which it
defined as any area where military construction had enhanced the defensive
characteristics of the terrain.
The weak link in this choreography of arms was de-mining.
While the 1st Marine Division had distributed extra engineer units across the
assaulting forces, they were still in short supply. Occasionally the advance
stalled while the infantry waited for engineers to arrive. The division’s
after-action report called for more training of the infantry in de-mining. When
armor was not present, as during the day on 25 September for the 1st Marines,
the pace of advance was slower and the cost higher. Several times, when dozer
blade-equipped Shermans tried pushing through the barricades without the
engineers, they were knocked out by mines.
The Korean War was the debut for one radical improvement in
US mobility, the helicopter, but this was not a mode of transportation ready
for the urban environment. The first generation HO3S-1 helicopters did
facilitate the rescue of downed pilots, medical evacuation, and the movement of
commanders around the battlefield, but they were vulnerable to small arms fire.
The Marines had only eight helicopters (the only helicopters then in Korea),
and several were lost to ground fire, resulting in a command policy to minimize
their exposure to fire.
The primary counter-mobility tool for US forces was
aircraft. Even several days prior to the Inchon landings, US carrier-borne
aircraft were roaming thirty miles inland to attack NKPA forces and restrict
any early North Korean reaction. Both US Navy and Marine Corps aircraft
maintained a continuous cap of twelve aircraft during daylight hours. On 16
September alone US air units reported destroying 200 trucks just south of the
38th parallel, in addition to seven tanks across the patrol zone. The NKPA
response to the danger of daylight movement was to reserve most of its
movements for the hours of darkness. To counter this, there were a number of
night fighters in use (F7F Tigercats and a night fighter version of the
Corsair), some flying from Japan, and then later out of Kimpo. C-47 “flare ships,”
each carrying hundreds of one-million-candle-power flares, sometimes supported
night interdiction missions.
At night, the two best US counter-mobility tools were mines
and harassing artillery fire. Each night US forces dug in, often laying out
mines to protect against the frequent NKPA night-time counterattacks. In the
large NKPA attack on the night of 25 to 26 September, the lead T-34 was knocked
out by a Marine mine. At times harassing fires were directed into Seoul, as the
4.2-inch Mortar Company of the 1st Marines did “throughout the night” of 23 to
24 September.
Logistics
The firepower-intensive operations in Seoul required large
quantities of ammunition, and while strained at times, the American logistical
system proved capable of supplying that need. Only two general shortages of
artillery ammunition occurred. As the demand for white phosphorous ammunition
sometimes exceeded the supply, artillerymen had to substitute high explosive
rounds. The Marine 4.5-inch rocket battery was rendered useless because the
wrong type of fuses had been brought from Japan, a problem that was not
corrected until after Seoul had fallen. This was discovered when a full salvo
of 144 rockets was fired into Yongdungpo, supporting the 1st Marines, and not a
single rocket detonated. During the NKPA night attack of 25 to 26 September,
Marine 105mm howitzer battalions ran low on ammunition, which interrupted their
fire missions, before overheated howitzer tubes did the same. Despite those
problems, as previously discussed, another US Army artillery unit was in range
and was able to shift its support to the Marines in Seoul.
Heavy ammunition consumption by the units in Seoul did draw
down the 1st Marine Division’s overall stockpile, but the supply flow was
“never seriously interrupted.” This was in part because Marine logisticians
aggressively pushed supply dumps forward. By 22 September several were in
Yongdungpo, and the first dumps were set up across the Han on 24 September.
While American logisticians established no dumps in Seoul until after its
capture, one was on the city’s outskirts on the first day of the assault, 25
September.
When local supplies ran low, US personnel usually found a
rapid remedy. During that same heavy attack of 25 to 26 September, an emergency
request came from the 3rd Infantry Battalion (1st Marines) for more ammunition.
The regimental supply dump was moving and could not respond. However, the supply
dump for another battalion in the regiment was in place nearby, so several
officers using a jeep conducted an emergency resupply from its stocks. They
navigated the debris-filled streets at night, directly resupplying the
companies in need while under fire. When the regimental dump arrived at 0330
that night, it sent several amphibious trucks full of ammunition to those same
companies. Captain Barrow’s Able Company ran low on supplies, as it spent a
night isolated in Yongdungpo. His men managed by scavenging some NKPA supplies
they captured, and then a resupply run of five American tanks arrived in the
morning.
Supplying the tanks in Seoul did present some difficulties,
but not sufficiently to detract from their supporting role. Even before the 1st
Tank Battalion shipped out from the United States, its personnel discovered a
nation-wide spare parts shortage for the M26 Pershing, which logisticians could
never solve during the Inchon-Seoul operation. The supply of 90mm high
explosive and white phosphorous ammunition for the M26 was low at times
(although not “critical”), and tank units shifted to using the Shermans with
their 105mm guns. The 1st Marines complained that their supporting armor spent
too much time away from the front line refueling and rearming at distant
resupply points. At times the advance of the infantry halted until the armor
returned. The armor supporting the Marine infantry was a mix of organic and
attached from the 1st Tank Battalion, and the Marines found the infantry
regiments lacked the maintenance capabilities to support these large
contingents of tanks. This was exacerbated by delays in movement of support
elements of the 1st Tank Battalion across the Han.
Several operational logistical factors were present during
CHROMITE, but the tempo of operations in the city was not affected. Some units
experienced resupply difficulties because they had not brought their full
complement of trucks, driven by shipping limitations and the rushed planning
for the Inchon landings. Another constraining operational factor was the Han.
The lack of bridging material, at least before Seoul was cleared, required all
units and supplies to move across via motorized pontoon barges, amphibious
tractors, or amphibious trucks, creating long lines at the three crossing
points. Helping matters was the success of US engineers in rapidly restoring at
least partial rail service in the Inchon-Seoul area, and the early capture of
Kimpo, into which US transport aircraft flew over 1700 tons of supplies from
Japan during the fighting in Seoul (25 to 27 September). US forces also
captured significant amounts of NKPA supplies in the advance on Seoul.
Dealing with the Population
During the abbreviated planning phase for Operation
CHROMITE, US planners addressed support for the civilian population and
stipulated an aggressive schedule for handing over responsibility to the South
Korean government. X Corps estimated that 15 percent of Seoul’s population,
which had been 1.5 million in 1949, would be destitute and require direct assistance.
To that end, the invasion fleet carried with it 2500 tons of rice for
distribution to civilians. US intelligence reports on the city included the
location of hospitals, water system components, power plants, and lists of
those civilians known to be hostile or friendly to the United Nations forces.
Medical care emerged as the salient service provided by US
forces to the population. In the first few days after the Inchon landings, only
the medical facilities of the 1st Marine Division were ashore, and those
facilities were overtaxed supporting the injured from the Marines, Army, Navy,
ROK, POWs and “hordes of civilian casualties.” Also in those early days, the 1st
Marine Division set up a hospital in Inchon for treating civilian casualties,
staffed with US personnel and some “rounded up” local Korean nurses. US forces
had some initial difficulty supporting this facility, but this was soon
corrected with supplies carried by the assault fleet, flown in from Japan, and
captured from the NKPA.
As US forces approached Seoul, it became apparent to the 1st
Marine Division Surgeon that the fight for Seoul would generate greater than
expected civilian casualties. He took this matter up with headquarters X Corps
on 25 September, stating his estimate of five thousand casualties would
overwhelm US military medical capabilities ashore at that time, and that there
could be political repercussions should this need not be met. Two days later, a
letter from the 1st Marine Division commander to Almond estimated a minimum of
five thousand civilian casualties and suggested “urgent attention.” Over the
next two days, the Marines began establishing two more civilian hospitals, in
Yongdungpo and Seoul. Given the overall transport shortfalls for X Corps, few
trucks were available to transport civilian wounded, but those most seriously
injured were moved in US military vehicles. Out of concern for the spread of
insect-borne diseases, resulting from the disruptions to civil services and the
number of unburied dead, US forces conducted insecticide “fogging” operations
in Seoul and Inchon. Several days before US forces entered Seoul, former city
officials were flown up from Pusan on US aircraft, including public health and
welfare personnel. Once US forces were inside the city, they established
collection points for civilian casualties in the city, and US troops passed
captured medical supplies on to the local South Korean officials. In the Inchon-Seoul
operation, civilians represented 35 percent of the patients treated by the 1st
Marine Division’s 1st Medical Battalion, and the medical company sent by that
unit into Seoul actually treated more civilians than it did Marines (615 vs.
518). Additional civilians were cared for at the regimental level, although the
1st Marines’ after-action report identified the need for expanded preparation
for this.
Key to the success in the X Corps support of the population
was the rapid transition back to South Korean civilian control, something
MacArthur had personally emphasized. The Americans flew Seoul’s mayor, police
chief, and other city officials up from the south into Kimpo. The mayor of
Seoul officially resumed his duties in Seoul’s City Hall on 28 September.
Under direction of the mayor of Seoul a program was
initiated to establish the civil police, public health and sanitation,
reconstruction of public utilities including water and electricity, and to
clear, in general, the destroyed portions of the city.
Civilian police units were slow to reorganize, but US MPs
augmented with ROK personnel and self-organized groups of civilians were
reasonably effective in restoring order in the city. Marine after-action
reports, however, noted that many units needed more civil affairs personnel.
The rules of engagement under which US forces operated in
the city allowed for the extensive use of firepower, understandably given the
operational military considerations and the nature of the foe. As Puller’s 1st
Marines encountered stiff resistance outside of Yongdungpo, he asked for a free
hand in applying artillery and air strikes inside the suburb, and Almond
“authorized the burning of Yongdungpo.” The 11th Marine Artillery Regiment
lamented the lack of proper 4.5-inch rocket fuses as they “Would have been very
effective in destroying the town of Yong-Dong-Po.” They also directed extensive
harassment, interdiction, and supporting artillery fire into Seoul itself. One
Marine 4.2-inch mortar company fired 700 rounds of high-explosive and white
phosphorous and reported “the burning out of several blocks within the city.”
Restraint in the use of firepower was occasionally evident, but this was most
often out of concerns for the safety of friendly military personnel.
An aggressive use of firepower made sense from an
operational perspective. The speed at which US forces captured Seoul had a
direct connection to the duration of the war in the minds of the American
commanders. To that end, US commanders needed an abundance of firepower to
overcome the delaying tactics of a determined defender. A shorter war would
mean fewer overall civilian casualties. Puller’s mix of regret and
determination were evident in his comments to the press.
I am sorry I had to use that stuff [155mm artillery] last
night. The Koreans won’t forget this in 500 years. I’m convinced the Reds are
holing-up deliberately to force us to use artillery and flame throwers.
Speed was also important for the welfare of the civilians
and American POWs. The Marines received reports from informants in the city of
NKPA atrocities there, including that approximately 50 percent of the damaged
buildings were due to NKPA arson, in a planned scorched earth policy. US units
also received reports of American POWs being killed by the NKPA in the city. A
captured NKPA memorandum “Directive Re Slaughtering of Captives,” dated 16 August
1950, complained that too many NKPA units were still slaughtering captured
Americans, and urged that they should stop as it was no longer useful since the
war effort was going so well.
The human cost to the civilian population of Seoul is a moot
subject in US after-action reports. The chaos of the battle and the preceding
three-month North Korean occupation explain the absence of an accurate count as
to the number of civilians actually present in the city, but the number was
likely a large proportion of the 1.5 million pre-war figure. Even the official
South Korean history of the war avoids the topic. In its eleven-page section
describing the battle and handover to South Korean government control, not only
is there no estimate of civilian casualties, there is not even a mention of
civilian dead. While the duration of the fight inside the city was short, the
liberal use of firepower by both sides probably cost considerable civilian
life. A gross estimate could be in the low thousands.
Conclusions
The capture of Seoul presented a range of problems,
including minimal planning for the fight in the city itself, a hasty operational
planning cycle, and some units that were recently created, but US forces
overcame these and proved capable of accomplishing their mission. Despite the
paucity of attention in the US military to city fighting in the period after
World War II, the Marines managed to break through determined resistance at
several points outside the city and clear Seoul in just three days. As was the
case in Aachen and Manila, the two key drivers behind that success were
transferable competence and adaptation.
Carried over from World War II, the USMC’s emphasis on
firepower and combined arms—in training, organization, and equipment—paid
handsomely on the streets of Seoul. The skillful blending of armor, infantry,
artillery, engineers, and air support allowed steady progress against the NKPA
barricades—which were themselves a blending of capabilities (mines, infantry,
artillery, and armor). When the NKPA chose to attack, Marine firepower was even
more effective, as when the NKPA’s offensive capability in the city was largely
destroyed on the night of 25 to 26 September. Equally as important, the
American logistical system was able to provide the large amounts of ammunition
needed for such a firepower-intensive approach. The NKPA did possess some
significant armor and anti-armor capabilities, at least on paper, but poor crew
quality and training resulted in a decided armor advantage for the Marines.
Unlike the previously examined battles in Aachen and Manila,
the Marines at Seoul had no recent experience that carried over into urban
warfare. The 5th Marines had just come from the Pusan Perimeter, but none of
the American units involved had fought extensively in urban terrain or dealt
with the NKPA on the defensive. The quality of Marine personnel, including its
small unit leaders, helped make up for that lack of experience. The Marine
doctrinal emphasis on aggression and initiative fit perfectly with the needs of
the urban landscape. Small unit leaders also contributed greatly to the NKPA’s
effectiveness, particularly in the hill mass northwest of the city.
Adaptation by US forces inside the city was minimized by the
short duration of the battle, but there were still some examples of adaptation.
The 1st Marines’ combined arms solution to the NKPA barricades was not fully
applied until their second day in the city, although only because problems with
crossing the Han delayed the arrival of its armor into the city. When the US
Army first lieutenant could not see the spotting rounds for the badly needed
artillery support during the NKPA night attack of 25 to 26 September, he
requested a switch to white phosphorous, which proved much more visible amid
the many burning buildings.
The greatest difficulties in Operation CHROMITE were induced
by higher-level decision making—the relatively low priority given to the
isolation of the city, and the direct approach taken by the 5th Marines into
the city. Unlike the commanders at Aachen and Manila, Almond gave low priority
to cutting off the city before beginning the assault. Perhaps this came from a
belief that the city would fall quickly, but his assigning of that task to his
two later arriving regiments resulted in the NKPA escape routes remaining open
during the battle. A 1st Marine Division intelligence report, produced at the
end of the battle, stated,
His [the NKPA] determined delay through the city has
afforded him ample time to regroup and reorganize his remaining forces for a
determined stand along a line of his choosing.
The route into Seoul from where the 5th Marines crossed the
Han took them directly into the NKPA’s main line of resistance. This both
delayed the capture of the city and weakened the 5th Marines sufficiently to
relegate them to a secondary role in the fighting inside Seoul. Once by plan,
and once by accident, US troops entering both Aachen and Manila had managed to
bypass the enemy’s main line of resistance.
The battle for Seoul was a decisive point in the Korean War,
and probably the most operationally important urban battle in US military
history. Of the 70,000 NKPA troops around the Pusan Perimeter, only an
estimated 25,000 made it back to North Korea. US forces, mostly Marines,
conducted the battle in an aggressive and largely competent manner, ending the
first phase of that war. Perhaps most impressively, it was conducted only three
months into a war that had shaken the United States out of its demobilized
daze. The battle also proved a strong rebuttal to the notion that nuclear
weapons had marginalized conventional ground combat operations.
