Operation Chromite The operational environment consisted of North Korean forces advancing to the Pusan Perimeter so as to surround it. North Korea had just conquered Taejon and was moving in the direction of the UN’s position, causing American forces and South Korean forces to retreat.

The dire situation facing the U.S. Eighth Army at the Pusan Perimeter was exacerbated by a steady decrease in strength that had continued since the conclusion of WW2: “Army forces consisted of four understrength divisions equipped with worn-out weapons from WWII.”[footnoteRef:1] The Army was using out-dated weaponry and the U.S. Eighth Army experienced logistical challenges due to the Korean landscape and air interdiction. Additionally, the Eighth Army was full of young men who had never experienced combat, had little training, and possessed inadequate heavy artillery.[footnoteRef:2] [1: Operation Chromite, II-1.] [2: Operation Chromite, II-1-2.]

General MacArthur’s vision for Operation Chromite relieves NKPA pressure on the U.S. Eighth Army in the Pusan Perimeter by sending new units into the battle as they became available for action. MacArthur’s use of amphibious operations and joint operations ensured that a complete defense and shift to offense could be conducted, and that is what put the NKPA in a defensive rather than in an offensive position. This in turn allowed the Eighth Army to prepare itself accordingly and set about reestablishing its position at the Perimeter.

2

General MacArthur’s vision for the operational environment once Operation Chromite was concluded (the end state) consisted of capturing Inchon and allowing the UN forces to retake Seoul. The end state was thus characterized by the U.S. Eighth Army’s taking control Inchon and supporting the takeover of UN troops in Seoul. The four point strategy employed to achieve this objective was to attack the rear of the NKPA and harm the enemy’s supply lines to the south, while threatening the NKPA’s capital at Pyongyang and leveraging political capital in the South by reasserting sovereignty in Seoul. These four decisive actions were designed to send the message to the NKPA that it was useless to wage a conflict with the South as this was tantamount to starting a conflict with the West, in which case it stood no chance of surviving if it did. The bulk of the vision, however, rested on taking Inchon via amphibious assault as a joint operations exercise. This was the first step in the vision as Inchon would serve as the base or foundation for the next step—the advance on Seoul and the severing of the lines of communication and supply of the enemy.

The plan for Operation Chromite was to make use of amphibious assault to take Inchon: “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.”[footnoteRef:3] The assault was planned and supported by joint operations and Marines and support from the air were available to assist in the landing. Once Inchon was taken, X Corps would head inland to take Seoul and cut the enemy’s communications and supply lines that were supporting the NKPA’s forces in the south. JTF 7 was there to assist in the landing by giving support to secure the area surrounding Inchon and the total effect of this joint operations approach was that the Eighth Army was completely supported. [3: Operation Chromite, II-6.]

3

As JP-5 notes, a key decisive point is a major event or factor (such as a turning point in strategy) that allows one to obtain an advantage over one’s enemy when enacted. As stated in the Joint Task Force Command and Control guide, “a commonly shared dynamic visual representation and associated Global Command and Control System (GCCS) data management tools can be used to integrate and manage relevant data sources” which will help a commander and his staff to identify decisive points.[footnoteRef:4] Two key decisive points for Operation Chromite were: 1) the use of asymmetric action—i.e., the joint operations involving UN sea and air combat power directed at the land forces of the NKPA, and 2) MacArthur’s vision which included a clear expression of goals and the way in which those goals could be achieved. The first of these key decisive points included understanding the vulnerabilities and weaknesses of the enemy and then planning joint operations attack that would focus on that vulnerability. By exploiting the enemy’s weakness, the U.S. was able to take what seemed like a strong offensive position...

As the NKPA could not operate in both the air and sea, as the UN and US forces could, it was at a significant disadvantage. [4: JP 3-33, IV-5.]
The second of these key decisive points included MacArthur personally assessing the situation, using his past experience and knowledge to plan a decisive operation that would use the data from the field and apply the strengths of the Western forces to the weaknesses of the NKPA. By personally assessing the environment and drawing upon his knowledge of how joint operations could allow the UN and U.S. forces to turn the tables on the enemy, MacArthur set about creating a vision for these same UN and U.S. forces, by getting a firm sense of the terrain and what was required. Then MacArthur provided clear and coherent goals supported by a strategic course of operations that was implementable and effective.

4

First, Operation Chromite reversed the situation at the Pusan Perimeter, and second, it placed the Allied forces in an advantageous position over the NKPA. The operation allowed for the breakout of the U.S. Eighth Army at the Pusan Perimeter and did this through reversing the course of action and then putting the Allies in a better position to win. The reversal maneuver came about after the failure of the air interdiction against the NKPA to impact the movement of the enemy. MacArthur turned to an amphibious joint operation that allowed the Allies to take Inchon, which was an important decisive point in the battle.

The second maneuver which allowed the Allies to obtain an advantage over the NKAP was the joint operation sea and air attacks against the NKAP, which resulted in cutting the supply line of the enemy and forcing the enemy to abandon its gained ground. This opened the path to retaking Seoul, and with the enemy’s supply line and communications line severed, the NKPA was in a weakened position and not disposed to prolong a conflict with the south or with the Allies. Thus, by first securing a foothold at Inchon through joint operations and then by attacking the enemy’s vulnerabilities, the Allies gained an advantage in the war. This was the asymmetric action that the NKPA simply could not copy: that is why “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.”[footnoteRef:5] [5: Operation Chromite, II-11.]

5

Joint Fires will support Operation Chromite for (1) landing forces at Inchon by providing protection against return fire from the enemy. It would provide support for (2) attacking the NKPA’s communications and supply lines by allowing the Allied forces to advance on their way to Seoul in spite of any retaliatory measures taken by the enemy. The Joint Fires support in severing the enemy’s lines would come by way of pinning down the enemy and cutting its lines in two so that the NKPA could not effectively regroup. Joint Fires would support interdicting any NKPA attempts to counterattack or reinforce forces as an element within the overall organization of the defense of the Allies in providing security for the advantage gained in Seoul: “An element is an organization formed around a specific function within a designated directorate of a JFC’s HQ. The subordinate components of an element usually are functional cells. An example of an element is the joint fires element.”[footnoteRef:6] This Joint Fires element contributed to the support of the operation by providing cover for the ground forces as they took Inchon and then headed inland to Seoul. [6: JP 3-33, II-12.]

6

The other Services (Air Force, Marines and Navy) provided General MacArthur with operational reach in Operation Chromite by contributing air, land and sea power to the fight against the NKPA. By operating in all three spheres, the Allies were able to leverage their power against the enemy, secure territories, exploit the enemy’s weaknesses, turn the tide of the war, and gain the advantage by taking Seoul. Making use of all the tools available to him, MacArthur effectively developed and implemented a strategy that was devised around the usage of these tools—i.e., the joint operations of the various military branches to ensure victory.

The operational reach provided an advantage to the Allies over just reinforcing the Eighth Army inside the Pusan Perimeter by providing support for securing the region from the air and from the sea, keeping communication and supply lines open for the Allies while closing them for the enemy, and providing…