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mobility. The Korean infrastructure was woefully inadequate; the scarcity of improved roads, airfields and ports in particular would frustrate and complicate the application of US military power (Figure II-1).

c. Within hours, news of the invasion was flashed to General MacArthur in Tokyo. On 25 June 1950, President Truman ordered MacArthur, as Commander-in-Chief Far East (CINCFE), to use his air and sea forces to support the ROK forces south of the 38th Parallel. MacArthur personally visited Korea on 29 June to protect evacuation of US personnel, help formulate an appreciation of the situation, and to develop recommendations for the Joint Chiefs of Staff (JCS) and the President.

2. Status of US Military Forces

a. American military power available within the theater was unprepared for the struggle it would face in the next few months. Army forces consisted of four understrength divisions equipped with worn-out weapons from WW II. They were manned by young men who, for the most part, lacked combat

“The military student does not seek to learn from history the minutiae of method and technique. In every age these are decisively influenced by the characteristics of weapons currently available and by means at hand for maneuvering, supplying, and controlling combat forces. But research does bring to light those fundamental principles and their combinations and applications, which in the past, have been productive of success. These principles have no limitation of time. Consequently the army extends its analytical interest to the dust buried accounts of wars long past as well as to those still reeking with the scent of battle.”

General Douglas MacArthur

“The vulnerability of the enemy is his supply position.”

General Douglas MacArthur

1. Introduction

a. In the predawn darkness of 25 June 1950, forces of the North Korean People's Army (NKPA) smashed southward across the border marked by the 38th Parallel to invade the Republic of Korea (ROK). The NKPA was a formidable force of at least 135,000 men. Many had been conscripts of the Chinese and Japanese armies and they were equipped with modern Soviet-supplied tanks, artillery and aircraft. In comparison, the ROK armed forces were trained only as a constabulary force and poorly equipped. Numbering less than 100,000, the army lacked armor, antitank weapons, and heavy artillery. Most soldiers were conscripts, and few units had ever trained above the company level. Air and naval forces were nearly nonexistent.

b. Although an ancient culture, Korea was an underdeveloped nation which had suffered greatly under Japanese occupation. The entire peninsula was extremely mountainous and compartmentalized, while the limited number of north-south and east- west lines of communication constricted

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Figure II-1. Joint Campaigning in Korea 1950

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seasoning. Focused on occupation duties, training was marginal and most units lacked the heavy weapons called for by their Tables of Organization.

b. The newly independent Air Force was represented in theater by the Far East Air Forces (FEAF) commanded by Lieutenant General George E. Stratemeyer. FEAF was primarily equipped with jet interceptors, designed for air defense of Japan against the perceived Soviet and Chinese threats. Reconnaissance, transportation and ground attack aircraft were scarce. Despite the shortage of transport aircraft, the Air Force was to play a critical role in delivering supplies and personnel to support ROK and US forces in the early stages of the war.

c. Vice Admiral Charles T. Joy, Commander, Naval Forces Far East (COMNAVFE), led a force which consisted of just one cruiser and four old destroyers. However, the US 7th Fleet, with an aircraft carrier, a cruiser, eight destroyers, and three submarines and commanded by Vice Admiral Arthur Struble, would soon be made available and would significantly improve the naval posture.

d. American forces in the rest of the world were just as poorly manned and prepared. This situation was the legacy of the rapid drawdown following the end of WW II and post-war budget cuts, driven partly by the belief that the atomic bomb had made conventional forces less relevant to national defense. The failure to maintain an adequately prepared force would extract a high cost in human suffering over the next few months.

e. MacArthur’s experience and capability as a joint force commander, the experienced Far East Command (FEC) joint planning staff in his headquarters (HQ) in Tokyo, and the leadership abilities of the officers who would serve as his subordinate commanders to some

degree offset the disadvantages that faced the United States that gloomy June morning.

3. US Response to the Invasion

a. Half a world away, President Truman and his advisors viewed the invasion from the north as a part of the ongoing communist confrontation with the free world. The President reversed previous US policy (which did not see Korea as vital to US interests) and ordered that actions be taken to evacuate US and United Nations (UN) dependents from Korea and to supply the ROK forces with ammunition and equipment. At the same time, the UN called for the People's Democratic Republic of Korea to halt its aggression and withdraw north of the 38th Parallel. This resolution was ignored, and the North Korean onslaught continued. While some ROK units resisted heroically, others dissolved in panic.

b. The President placed the US 7th Fleet under MacArthur's operational control (OPCON) and authorized its movement to the waters off Formosa. This move signalled the Chinese that the United States would not tolerate any widening of the conflict. Concern about expansion of the fighting, both in the Pacific and to other parts of the world, overshadowed all US decisions that followed.

4. United Nations Reaction

On 27 June, with NKPA forces continuing the invasion, the UN passed a milestone resolution calling on member states to furnish military assistance to the ROK to “. . . repel the armed attack.” This was the first time that the UN took such action. On that date Truman expanded his 25 June authorization of air and naval attacks south of the 38th Parallel to include all of Korea. He also authorized the employment of Army forces at the southern port of Pusan. The next day Seoul fell.

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5. MacArthur Assesses the Situation in Korea

a. On 29 June, MacArthur arrived in Korea and rapidly assessed the situation. He realized that he was facing a tough opponent and that half measures would not be effective. From the south bank of the Han River, he watched the retreating ROK forces and realized that “only immediate commitment of ground troops” could stem the invasion. Unfortunately, he had few ready forces and only limited transport available to rapidly commit them. Additionally, he had no authority to commit ground forces outside of the southern port of Pusan.

b. MacArthur quickly informed the JCS that he felt the ROK forces would be unable to stop the invasion and that a major commitment of American power was required. His clear understanding of the nature of modern warfare was evident in his words — “ . . . To continue to use the forces of our air and navy without an effective ground element can not be decisive. Unless provisions are made for the full utilization of our Army-Navy-Air team in this shattered area, our mission will at best be needlessly costly in life, money and prestige. At worst, it might be doomed.” The employment of ground forces was authorized within 24 hours of receipt of this message.

c. MacArthur first began to consider an amphibious landing in the enemy rear area while he stood on the south bank of the Han River. He was predisposed to favor this type of an operation; his successful campaigns across the Pacific in the Second World War were based on the concept of applying Allied air, naval, and ground strength against enemy weakness. Amphibious landings in areas where they weren’t expected had kept the enemy off balance and allowed the Allies to maintain the initiative. It was only natural that he would consider this type of operation when assessing his options to save the situation in Korea.

“The deep envelopment based on surprise, which severs the enemy's supply lines, is and always has been the most decisive maneuver of war. A short envelopment which fails to envelop and leaves the enemy's supply system intact merely divides your own forces and can lead to heavy loss and even jeopardy.”

General Douglas MacArthur

6. Communist Forces Advance

a. Unconcerned with UN and US actions, and ignoring significant losses inflicted by the retreating ROK forces, the enemy reinforced its initial success and continued the advance. On 3 July the airfield at Kimpo and the port of Inchon fell. Enemy aircraft began operating out of Kimpo, although US forces soon secured air supremacy and NKPA air played little role in the battles to come. Concurrently, the small northern navy was completely destroyed and a tight blockade of the sea approaches to the peninsula established. By 4 July, the enemy ground advance had reached Suwon, 25 miles south of Seoul. At the same time the lead elements of the 24th Infantry Division, better known to history as Task Force Smith, were landing at Pusan.

b. These unprepared soldiers were committed to buy additional time to bring appropriate forces into the area. MacArthur later characterized his costly piecemeal commitment of these units as an “arrogant display of strength.” He and his staff hoped that this desperate rear guard action would stabilize the front by causing the enemy to slow his advance and proceed cautiously when he realized he was up against US troops. It would also boost the morale of the ROK armed forces by showing them they were not alone. Dawn on 5 July found Task Force Smith blocking

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from Korea, and the 140 mile long Pusan Perimeter (Figure II-2) was established. The desperate fight to keep this foothold on the peninsula absorbed all reinforcements arriving in theater. Without the strength and resilience these forces provided, it is doubtful that Eighth Army could have held on.

8. MacArthur Plans His Riposte

a. While these events transpired, MacArthur remained focused on regaining the initiative. Already he had intuitively arrived at the solution; now he needed a fleshed-out plan and a force to execute it. Elements of his staff at FEC, led by Major General Edward M. Almond, went to work on the plan as early as 4 July. In his first request for reinforcements sent to the JCS on 7 July, MacArthur stated that his main purpose was to “. . . fully . . . exploit our air and sea control and, by amphibious maneuver, strike behind his mass of ground forces.”

b. Preliminary planning called for a late July landing, but the reality of the strength of the enemy and the weakness of the UN forces compelled delaying the operation. The forces which would have conducted the landing were instead being rushed ashore to maintain the defenses around Pusan.

c. Planning for the landings was conducted at FEC HQ in Japan by the Joint Strategic Plans and Operations Group (JSPOG). A number of alternatives were developed and considered in great detail. By the 23rd of July, JSPOG came up with three options for consideration. Plans 100B, 100C, and 100D called for landings at Inchon (west coast), Kunson (west coast), or Chumunjin- up (east coast), respectively.

d. On 12 August, MacArthur issued CINCFE Operation Plan 100B, code named Operation CHROMITE, with Inchon as the target to be seized by the amphibious assault.

the main road between Suwon and Osan. Despite the task force’s heroic efforts, a lack of effective anti-tank weapons led to defeat.

7. The Defense of Pusan

a. While these desperate battles were fought, the United States and UN continued to take the actions necessary to bring their power to bear on the peninsula. On 8 July, at the request of the UN, Truman named MacArthur Commander-in-Chief of the United Nations Command. On the 13th, Lieutenant General Walton H. Walker, commanding the Eighth United States Army, assumed command of all ground troops and responsibility for ground operations in Korea. MacArthur’s air and naval component commanders likewise assumed responsibility for their respective areas, with forces of other nations joining them as they arrived in theater.

b. As June gave way to July, NKPA spearheads continued their southward advance. South of Taejon they divided into two separate thrusts, one along the west coast and the second straight for Pusan, but their pace was slowed by logistic difficulties and terrain and by the increasing tempo of air interdiction. The cost of advancing in the face of heavy and effective UN air attacks continued to mount for the NKPA. Air interdiction alone, however, would not suffice. By late July, the US 25th Infantry and 1st Cavalry divisions had deployed from Japan and joined the 24th Division in Korea. They were shortly followed by elements of the 5th Marine Regiment, filled out to a provisional brigade by other Marine units. This infusion of fresh manpower, armed with 3.5 inch anti-tank rockets airlifted from the United States along with other US and UN troops deploying from around the world, began to turn the tide. UN forces were slowly pushed back until they reached the Naktong River. Here Walker and MacArthur decided that they must stand and fight or be ejected

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In recognition of the complex nature of an amphibious operation, ten Marine Corps officers and two Navy officers were attached to the planning staff on 19 August. This would guarantee that their special expertise was immediately available.

e. The plan called for X Corps (to be formed around the 1st Marine Division and the 7th Infantry Division) to execute a phased amphibious landing at Inchon (Figure II-3), then drive inland to secure Seoul and cut the enemy’s main lines of communications and resupply to his forces committed in the south. The initial assault by the 1st Marine Division was to be followed by the 7th Infantry Division and ROK Marine Forces. Simultaneously, the Eighth Army would launch a major supporting attack, eventually linking up with X Corps forces south of Seoul. MG Almond was named to command the X Corps, with the staff primarily hand selected

from the FEC staff. The staff assumed that the landings would end the conflict and they would return to their normal billets in Japan.

“The history of war proves that nine out of ten times an army has been destroyed because its supply lines have been cut off . . . We shall land at Inchon, and I shall crush them [the North Koreans].”

General Douglas MacArthur

9. Forces for the Landing

a. Putting together the forces to make the landing was a major challenge. The enemy continued to threaten the Pusan perimeter, and MacArthur had no forces to spare. The continued NKPA pressure on Walker at Pusan forced MacArthur to throw units into the fight as they became available. Additionally, MacArthur felt strongly that a successful amphibious operation required a Marine

Figure II-2. The Pusan Perimeter, September 1950

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division. Washington initially balked because a Marine division was not available, the Corps having shrunk to a post war low of less than 80,000. A major reserve callup would be necessary to field a full division; but MacArthur was adamant and his persistent arguments, coupled with his status and reputation, carried the day.

b. Major General Oliver P. Smith assumed command of the 1st Marine Division at Camp Pendleton in late July and was ordered to bring it to full strength (less one regiment) by combining it with the cadre forces of the 2nd Marine Division and recalled reservists. The division was to sail for Korea by 15 August. Trained Marines were so scarce that, in order to fill the division, a battalion was pieced together from various Marine forces in the Mediterranean and sent directly to Korea.

c. One brigade assigned to this newly fleshed out division was already fighting in the Pusan area. The 1st Marine Provisional Brigade had been activated on 5 July at Camp Pendleton. It was composed of the 5th Marine Regiment, a battalion of the 11th Marines, and Marine Air Group 33. It sailed for Japan on the 14th, but the situation at Pusan was so desperate that it was diverted directly to Korea. It landed at Pusan on 2 August and went straight into the battleline. Prior to the Inchon landing, it had to be pulled out of combat, moved back to Pusan, refitted, embarked, and landed as a part of the assault force — all in less than 10 days.

d. The Army's 7th Division was, by August, at less than half strength. Key officers and noncommissioned officers as well as equipment had been diverted to bring the 24th, 25th, and 1st Cavalry Divisions up to

Figure II-3. The Inchon Landing

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b. Washington was concerned that the geographic problems at Inchon would cause the landings to flounder and result in a major reverse and heavy loss of life. Conversely, MacArthur was utterly convinced that the landings would succeed, and his confidence won the day. Weighing the risk against the potential gain, MacArthur was certain that a less ambitious amphibious envelopment at a less difficult site, as favored by many in Washington, would not be decisive and would condemn the Eighth Army to a brutal fight north from Pusan.

c. Two weeks prior to the landings, the Navy introduced a three-man team into the Inchon area to pinpoint enemy defenses and verify tide and terrain data. This daring and resourceful team, led by LT E. F. Clark (USN), enlisted the aid of loyal ROK civilians and succeeded in passing a great amount of essential information to the planners. On the night preceding the landings Clark even succeeded in lighting one of the principal navigation lights in the approach channel to guide the attack fleet.

d. Even without the geographic challenges presented by Inchon, MacArthur understood amphibious operations to be highly complex. He established Joint Task Force (JTF) 7, under the command of Admiral Struble, to finalize the plan and execute the landings. The operation plan (OPLAN) directed naval Task Force (TF) 90, RADM J. H. Doyle commanding, to isolate the landing site, conduct the amphibious assault to secure the Inchon area, land the follow-on and reserve forces, provide air and fire support, and provide other support as necessary. The landing was to be preceded and supported by a heavy naval bombardment from US and British ships of the naval Gunfire Support Group (TF 90.6, RADM J. M. Higgins) anchored close offshore.

e. Air Force bombers flying from Japan would help isolate the landing area by

strength. Between mid-August and early September, the 7th received priority of replacements and was augmented with nearly 8,000 Korean soldiers. By the time of the landings, both the 1st Marine and 7th Infantry Divisions were fully manned and equipped.

“The best I can say about Inchon is it is not impossible.”

RADM James H. Doyle Commander Assault Force (TF 90)

23 August 1950

10. Amphibious Landing Challenges

a. Inchon presented a vast array of challenges to the landing force (Figure II-4). Extremely high tides, narrow channels, high seawalls, extensive mudflats, and enemy resistance would all have to be overcome if the landings were to succeed. Additionally, the harbor approaches to Inchon were guarded by the fortified island of Wolmi-do. While the staff worked to address these problems, MacArthur focused his effort on convincing the JCS that the risks were minimal and that the operation should go ahead.

“The Marquis de Montcalm believed in 1759 that it was impossible for an armed force to scale the precipitous river banks south of the then walled city of Quebec, and therefore concentrated his formidable defenses along the more vulnerable banks north of the city. But General James Wolfe and a small force did indeed come up the St. Lawrence River and scale those heights. On the Plains of Abraham, Wolfe won a stunning victory that was made possible almost entirely by surprise . . . Like Montcalm, the North Koreans would regard an Inchon landing as impossible. Like Wolfe, I could take them by surprise.”

General Douglas MacArthur

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attacking strategic targets so that the enemy could not move reinforcements by land. While these actions were underway, TF 91 (RADM W. G. Andrews, R.N.) would serve as a blocking and covering force so the landings would be free from interference from the sea.

11. The Amphibious Landing

a. The amphibious objective area was established as an arc extending 30 miles inland from the landing beaches. Priority close air support within this area would be provided by Navy, Marine Corps and British air units of the Fast Carrier Group (TF 77) and the Air Support Group (TF 90.5). Air Force close air support for the landings was not part of the plan. Long flight times from Japan as well as communications and other coordination challenges made such geographic divisions of labor among the components the norm in Korea.

b. Fifth Air Force (Major General Earle E. Partridge) provided general air support for the invasion by isolating the objective area. As part of this effort commencing on D-10, a major, 7- day effort was launched against the rail network north of Seoul. Fifth Air Force was also charged with furnishing air-ground support to the Eighth Army in the south and with the on-order mission of air delivery of the 187th Airborne Regimental Combat Team.

c. The 3rd Battalion, 5th Marines, the lead element of the 1st Marine Division — the Landing Force — made the initial assault on Wolmi-do with the high tide at dawn on 15 September and crushed enemy resistance. The main landings by the rest of the division followed on the next high tide 11 hours later. The enemy was completely surprised. Intelligence estimates prior to the landings put as many as 18,000 troops in the Inchon - Seoul area but, as it turned out, only 5,000

INCHON CHALLENGES

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Necessity to hold Pusan perimeter Extreme operational reach for US based forces Lack of US operational amphibious landing or sufficient practice since 1945 Military requirement and political effect of recalling reserves to provide

sufficient forces Scarcity and piecemeal arrival of trained and ready forces Limited operational range and numbers of land-based close air support aircraft OPSEC Potential for discovery of invasion fleet in Yellow Sea Hours of daylight available Number of days available per month with sufficient channel depth for large

craft Extreme tidal range, causing inability to reinforce from sea except at high tide

and immobility of landing craft at low tide Landing sites featured concrete seawalls, not shelved beaches Unknown number and strength of defenders Restricted, narrow, tortuous, single ship channel for entry Fortified Wolmi-do Island dominated the single harbor entry channel

Figure II-4. Inchon Challenges

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combat troops were there initially to oppose the operation. Although they put up stiff resistance, X Corps’ powerful and unexpected thrust could not be turned back. By the evening of the 16th, MajGen Smith informed Admiral Struble that he was sufficiently established to assume responsibility for operations ashore.

12. A Simultaneous Attack

a. As events unfolded in the north, the Eighth Army supporting attack was about to kick off in the south. On the morning of 16 September, Eighth Army launched its supporting attack against the more than twelve enemy divisions deployed against it. The enemy had just drained its strength in an unsuccessful 2- week offensive aimed at breaking the UN perimeter. Attacking UN forces still met fierce resistance but, under heavy air attack by Fifth Air Force (over 640 close air support sorties were flown in support of the US I Corps on 18 and 19 September), with its rear area threatened by X Corps, and with its supply lines under increasingly heavy air attack, NKPA resistance began to wane. On 19 September US and British units succeeded in breaking out, and by the 20th were exerting strong pressure as they moved toward Taejon.

b. The two nearly simultaneous attacks were beginning to have the desired effect. Unable to resupply or reinforce, and under constant air and ground attack, the enemy was pushed back along the entire Pusan line more than 70 miles within a week. To help demoralize the enemy, tens of thousands of psychological warfare leaflets were dropped over enemy lines to encourage surrender.

UNITED NATIONS FORCES HAVE LANDED AT INCHON

Officers and men of North Korea. Powerful UN forces have landed at Inchon and are advancing rapidly. You can see from this map how hopeless your situation has become. Your supply line cannot reach you, nor can you withdraw to the north. The odds against you are tremendous. Fifty-three of the fifty- nine countries of the UN are opposing you. You are outnumbered in equipment, manpower, and firepower. Surrender or die. Come over to the UN side and you will get good food and prompt medical care.

Translation of UN leaflet dropped throughout Korea

Inchon presented a vast array of challenges to the Marine landing force, including the Inchon sea wall.

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c. By 17 September, the 1st Marine Division had recaptured Kimpo airfield. Kimpo was back in action as a UN air base by the 18th. The Fifth Air Force immediately began an airlift of over 200 tons of supplies a day, which permitted Marine Aviation to move off the carriers. Now ashore, they could fly more, longer, and deeper missions. The next morning, the 7th Division and ROK Marine forces landed at Inchon and moved rapidly inland. The 7th Division turned to block any enemy attack from Suwon and the south, while the ROK Marines joined the 1st Marine Division in the attack to secure Seoul. With its flanks secured, the 1st Marine Division turned north on the morning of the 20th to begin the 6-day battle to clear Seoul. Bitter NKPA resistance ultimately forced commitment of the ROK Marines, 7th Division’s 32nd Infantry Regiment, and 187th Airborne Regimental Combat Team (a portion of the theater reserve) to the battle for Seoul.

d. Constant attack on all sides finally broke the NKPA resistance and the army collapsed. By the end of September the North Korean People’s Army ceased to exist as an organized fighting force in South Korea. MacArthur's prediction had been accurate.

13. MacArthur and Joint Employment Considerations

a. UN operations in Korea in 1950 showed how a superior force can conduct simultaneous combat operations along external lines of communications. Despite extremely long lines of supply (stretching to dozens of nations), UN forces possessed sufficient strength to successfully converge upon the Korean Peninsula with overwhelming power.

b. The use of asymmetric action is well illustrated in this operation by the application of UN air and sea combat power against the ground forces of the NKPA. This application of joint force strength and capabilities against enemy weakness throughout the entire battlespace allowed MacArthur to stabilize the situation and find a way to exploit the potential of his forces. Throughout the campaign, the advantage of being able to operate in the air and at sea, where the enemy could not, was important to success. MacArthur’s early and continuous leveraging of his dimensional advantage capitalized on UN strengths and slowed the attack of a numerically superior ground force operating along normally advantageous

US Marine landing forces were carefully timed for maximum effect.

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internal lines. Once UN and ROK ground forces were reinforced and re-equipped, the synergy created by the synchronized application of sea, land, and air power created a favorable overall combat ratio which secured strategic advantage for MacArthur and allowed his forces to destroy the enemy.

c. From the start, MacArthur demonstrated a clear understanding that to obtain victory, he needed to seek the earliest opportunity to conduct decisive joint offensive operations. From the day he arrived in Korea to assess the situation, he began formulating a plan to capitalize on UN forces advantages to launch an amphibious landing in the enemy rear. While taking action to stabilize the situation, he envisioned how he wanted the battle to be fought and began planning for the future. His initial concept for a landing in July had to be delayed, but he and the planning staff never lost sight of the real key to victory. This vision and determination to launch an early offensive positioned the command for a rapid transition between the defense and the offense when circumstances in September permitted. Without his foresight and the hard work of his joint planning staff, a major operation such as Inchon could not have been launched in the short time available, and the final outcome could have been decidedly different. Preparation and continuous planning were the keys to seizing the initiative when the opportunity presented itself.

d. The rapid assimilation of multinational forces into an effective fighting command in this operation should not be overlooked. From the beginning, Allied forces joined the command and immediately played critical roles. Effective coordination of US and ROK army forces with supporting Australian and British air and ground forces were essential factors in stabilizing the Pusan Perimeter. Part of this effectiveness can be traced to the World War II combined operations experience of MacArthur and most senior

leaders, but part must be attributed to the clear purpose and simple objectives of the force. UN solidarity in condemning NKPA aggression and the willingness of so many nations to play an active part in repelling the invasion provided the unity of effort necessary for smooth operations on the battlefield.

e. The demonstrated professional competence of the total force is another point worthy of study in Operation CHROMITE. US forces were able to recover from earlier unpreparedness to a great extent because of the residual skills of the reserve forces. Many recalled troops were seasoned veterans of World War II who were able to quickly reestablish their military competence. The expeditious integration of reserve and active units into a highly successful fighting force, able to conduct an extremely complicated amphibious maneuver in an exceptionally short time with almost no opportunity for face-to-face coordination and no chance to operate together, is unparalleled. While it could be argued that MacArthur had no choice but to use this kind of force, there is no evidence that he or any other leader had less than total confidence in the ability of these units to accomplish the mission regardless of all of these difficulties.

f. Very early in the campaign, MacArthur perceived that the enemy relied on overextended lines of communications. Accurate identification of the enemy lines of communication in the Seoul area was a necessary prerequisite for destroying the enemy force. Similarly, MacArthur’s willingness to pay the high price of piecemeal commitment of forces as they became available to slow the NKPA advance and then to maintain the Pusan Perimeter is a good example of protecting a friendly center of gravity. Although this was a costly decision, he understood that it would be hard, if not impossible, to recover

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vulnerable position. When the Inchon landing was followed one day later by the breakout of Eighth Army, the enemy found itself in an untenable position and was routed. Unfortunately, UN forces would commit the same error in the near future when they advanced to the Yalu River.

i. MacArthur well understood the complex nature of amphibious operations. He and many of his subordinate leaders and planners had experience with amphibious landings during World War II. During that conflict, amphibious operations had only been mounted after exhaustive planning and rehearsal. In the fall of 1950 these luxuries were simply not available. MacArthur’s tenacious pursuit of a Marine division to spearhead the assault, and the assignment of experienced Marine Corps and Navy officers to the planning team in Tokyo, indicates clearly that all involved understood how difficult the landings would be.

j. During the initial planning for Operation CHROMITE, X Corps reported directly to CINCFE, and all naval forces in

The synchronized application of joint forces provided the United States with an overwhelming military advantage.

from an ejection from the peninsula. MacArthur weighed the risk and cost associated and acted as he did because he realized that the UN forces had to hold on to this foothold in order to maintain their freedom of action.

g. The landing at Inchon was a classic coup de main that used surprise and an agressive supporting attack to overload the enemy’s ability to resist. This horizontal escalation of operations exceeded the enemy’s capacity to respond effectively. The enemy’s failure to anticipate MacArthur’s use of his tried and true recipe for success, amphibious assault in an unexpected quarter, allowed UN forces to control the Inchon - Seoul area. This gave the UN control of a decisive point: the enemy communication network that emanated from there to the NKPA forces in the south.

h. The enemy also failed to realize that it had overextended its offensive operations southward beyond the capabilities of logistic support. Failing to recognize this culmination point placed enemy troops in a

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theater reported to MacArthur through COMNAVFE. With the establishment of JTF 7 by MacArthur, X Corps (TF 92) became a subordinate of JTF 7 for the embarkation and assault phase of the operation. During this phase, parallel chains of command for the naval and ground forces operated within JTF 7. This technique is essential to ensure fully integrated and coordinated effort at all levels. The complexity of amphibious operations and the interdependence of the Services makes functioning parallel chains of command a key aspect of success. Once the embarkation and assault phase was completed and the exploitation phase of the operation begun, X Corps (along with its organic supporting air) left JTF 7 and again reported directly to CINCFE.

k. Although Air Force units were not part of JTF 7, elements of the 5th Air Force did operate in support of the amphibious task force. The attacks against the rail lines north of Seoul certainly impeded enemy reaction and contributed to creating the conditions necessary for a successful landing. The synergy orchestrated by MacArthur through his very capable melding of the complimentary facets of ground, air, and naval power led to the success of Operation CHROMITE.

l. JTF 7 established an amphibious objective area around Inchon that clearly defined the area that had to be controlled by the invading force. It was sufficiently deep to ensure that space would be available to accomplish objectives and facilitate future operations. The commander of the landing force established three phase lines to control movement and attack over the approximately 8 miles between the landing beaches and the beachhead line. The number of control measures required underscores the difficulties involved in coordinating amphibious assault forces. These phase lines also served to control ground attack by aircraft. No attack

was permitted short of the line without ground permission. Once the beachhead line was secured, the assault phase of the operation was concluded and the exploitation phase begun.

m. The world had greatly changed in the 87 years between the fall of Vicksburg and the outbreak of the Korean War. Economic prosperity had cemented the American military leadership role that emerged from World War II and emboldened the nation to take on a greater role in world affairs. No longer did events far from US shores seem so remote. Two world wars had shown the United States how costly it was to remain uninvolved. The UN offered the promise of resolving problems before they became wars and, along with most other nations of the world, our nation actively embraced this promise.

n. While these economic, political, and social circumstances were unfolding, an explosion of technology placed additional tools in the hands of the commander. These tools were more lethal and allowed a more complete exploitation of the possibilities of three-dimensional warfare. This same technology made the world smaller and quickened the pace of operations. Only 82 days elapsed between the northern invasion of the ROK and the Inchon landing, and only another 15 days passed between the landing and the destruction of the enemy. This operation was engineered by a UN force that had to be manned, equipped, delivered, assembled, supplied, and successfully employed on a remote, undeveloped peninsula. In contrast, it took nearly 9 months to mount the Vicksburg Campaign.

o. The Korean War was the first armed conflict the United States fought after the passage of the National Security Act of 1947 as amended in 1949. These legislative actions formalized many concepts and procedures that had informally evolved in our

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defense establishment in response to the challenges of World War II. There were many reasons for adopting such changes in the roles and relationships between the Services, JCS, and theater commanders; one of these was

the recognition that success on the modern battlefield demanded that we capitalize on the synergy that jointness provides. Modern warfare demands a joint approach. This realization changed forever the way we fight.