On 25 June 1950, North Korea forces launched a surprise invasion on South Korea under the command of Kim Il-sung and the North Korean People’s Army. During this time, the North Korean People’s Army forced through the 38th parallel and pushed through the unprepared Republic of Korea forces to the Southeast Pusan peninsula. The approximately 125 mile defensive perimeter was the point where United Nation forces withdrew to by August, 1950 and held that Southeast position of the peninsula. While UN forces were outnumbered, commanders were in search for a new course of action that would help skew the war in favor of them. At this point, General of the Army Douglas MacArthur first conceived his plan for what would become the Battle of Inchon. Inchon is located in the Northwestern corner of modern South Korea and was a key location for the North Korean forces. Inchon, located just 25 miles west of the nation’s capital, Seoul, was a key location for North Korean resupplies. Friendly intelligence and air reconnaissance observed that there were two major supply lines that were along the two major highways coming from both the northeast and northwest. It was through these two major supply lines that North Korean forces were able to then disseminate supplies throughout the South Korean peninsula and ultimately down to the Pusan area in the southeast corner. Because Inchon was such a key location for enemy resupply, General of the Army MacArthur chose to attack the enemy at this point. Many criticized General MacArthur’s decisions to plan an attack on Inchon for many reasons. To start, an amphibious attack on Inchon would be difficult due to the disadvantageous terrain, high and sporadic tides on shore, and the fact that the seawalls were easily defendable. However, General MacArthur chose this type of attack on this specific location because of these facts, stating that the enemy would not expect an attack from such a disadvantageous point. The mission was to capture Inchon, Seoul, and disrupt enemy resupply into the rest of the South Korea peninsula.
General MacArthur then held a conference in August in Tokyo, Japan with the head commanders of the armed forces and other UN commanders to discuss the planning of an amphibious attack, known later on as Operation Chromite. During the planning phase of Operation Chromite, General MacArthur tasked Major General Edward Almond as the Corps Commander for the operation. The 10th Corps was created and had at its disposal the 1st Marine Division based out of California (and at that point deployed throughout the world), and the Army 7th Infantry Division. General MacArthur then had to plan the way in which he would initiate the attack due to the tidal conditions on the Inchon shore. Because the tidal conditions were so poor and so disadvantageous, studies that were conducted showed the mid-September would be the more effective time to initiate the attack. However, special tactics were still necessary in order to accomplish the mission in this area. Mud flats were seen to be present during low tides, so to combat this problem, waves of troops would be sent in and be required to wait approximately 3 hours before reinforcements could be sent in. Now that the planning phase was near complete, orders were soon made to prepare the area with air strikes and other bombers.
Two days prior to the initial attack on 15 September 1950, pre-invasion bombardments were ordered. On 13 September and 14 September, B-29 Bombers and other bombers were sent in for air strikes on Inchon and surrounding areas in order to prepare the area for invasion that would soon follow. Battleships from UN forces would fire on the Inchon area beforehand and also attack up to four other coastal cities in order confuse the enemy before the invasion. Additionally, UN forces sent six major battleship destroyers to hone in on the enemy and initiate contact. Once the enemy land batteries were located, their location was recorded and processed so that their location was known and pinpointed for naval and air attacks later on during the operation. Now that the pre-invasion bombardment was established and complete, Operation Chromite was ready to begin the next day.
On 15 September 1950, UN naval ships left Japan with the 10th Corps troops heading for the west coast of Korea. At 0600 that day, the 3rd Battalion, 5th Marine Regiment would land on a local island off the coast of Inchon to secure the location for the attack to commence. At 1800, during high tide, the remainder of the 5th Marine Regiment and the 1st Marine Regiment would simultaneously attack Inchon from the North and South, respectively. They would attack the "Green Beach" on Wolmi-do Island. The attack was constructed into three elements, attacked in separate areas on the shore, separated into “Green Beach” “Red Beach” “Blue Beach”. Each of these locations were advantageous in their own ways and combined to create an overall advantage in the mission to capture Inchon. Later on, the 7th Marine regiment would also be used for support in the operation. During the entire operation at this time, General MacArthur would be observing from the commanders ship off the coast. While the Marine regiments were attacking Inchon and securing the location, the Army’s 7th Infantry Division would enter through Inchon and head south toward Suwon in order to establish a blockade along that major road and also create a flank on the southern end. The intent of this was to set up a double sided attack on North Korean forces in the center of the peninsula since there were already friendly forces all the way on the southeast peninsula in Pusan. While these attacks were occurring, due in part to the tidal conditions of the region, reinforcement capabilities at that time were not sent in for another ten hours. Despite this minor disadvantage for the UN forces, North Korean and Communist forces soon surrendered after only like opposing force and Inchon was ultimately captured and secured.
Once Inchon was secure, General of the Army MacArthur came to visit Major General Almond, 10th Corps Commander, to discuss future operations of the 10th Corps on 19 September 1950. Following this meeting, the 5th Marine Regiment travelled along the west bank to cross and secure the Han River for future amphibious attacks. This was the greatest barrier between Inchon and Seoul. Although the river was wide and the terrain was not advantageous, it was soon secured by the 5th Marine Regiment for future operations.
While the Han River was being secured, the 8th Army, commanded by Lieutenant General Walton H. Walker, headed for Seoul now that the North Korean and Communist forces had resupply efforts cut off by the 10th Corps’ success. In a turn of events, on 17 September, the Kimpo airfield was captured and secured, soon becoming operational by the 5th Marine Regiment. The Kimpo airfield was now capable of airlifts and friendly resupply and had nearly 400 tons of new supplies come in daily for supporting forces. General MacArthur now visited the Kimpo airfield to further consult with his fellow combat commanders and to continue to plan for the capture of Seoul and defeat the enemy forces. It was at this point that the 187th Airborne Infantry Regiment was called up from being in reserve in Japan. On 23 September they were called up and ordered to capture and secure the Kimpo peninsula, a bordering area of Inchon and Seoul. Once these supporting elements were ordered and established, it was time for the main effort to capture and secure the capital of Seoul.
On 24 September, the 5th Marine Regiment headed for Seoul along with support from the 1st Marine Regiment as well. Now in more suburban warfare environment within the heart of the city, various communist units held buildings in the area. Then while this was underway, the 7th Infantry Division was ordered to now enter Seoul from the south to aid in support after just successfully capturing the Suwon airfield. Now that these various units were attacking Seoul from nearly all angles, 10th Corps Commander Major General Almond ordered the 7th Infantry Division to additionally commit a regiment to cross the, now secure, Han River, and capture the South Mountain. Their follow on mission was to flank Seoul from the south in supporting the other units already there at this time. On 25 September at 0630, the Army regiment that was sent reached the bank and took small arms contact. Despite this, by noon they captured South Mountain, which was a major terrain feature with various advantages to it.
Now that units were placed on all the surrounding points of Seoul, the UN forces were gaining momentum and advantage over the area. On 26 September, North Korean enemy forces were forced out of the city. Soon after, on 27 September, the 7th Army Division troops met up with the 1st Calvary Division, leaving many communist troops trapped by US forces in the middle of the peninsula. On 29 September, General MacArthur participated in the Seoul liberation ceremony, in which he restored order and power to the South Korean authorities. At this point, the 10th Corps was relieved of all tactical responsibilities on 07 October.
After just 22 days, the mission was complete and the UN forces, under General MacArthur’s command, were able to capture and secure Inchon, Seoul, and defeat the enemy at key resupply points. Operation Chromite also suffered many casualties. Throughout the battle, 566 were reported killed and 2,713 reported wounded for the UN forces. The North Korean People’s Army lost an estimated 35,000 killed, captured, or wounded.
The aftermath of the Battle of Inchon was a turning point in the Korean War because of the advantage it then gave UN forces in what seemed to be a soon defeat when they were cornered at the Pusan peninsula. Although many criticized General MacArthur for his initial plan, the surprise and methodical planning of Operation Chromite was seen as a success for UN forces.
When analyzing the Battle of Inchon, we see that all nine principles of war were evident during this battle. We will see that Mass, Objective, Offensive, Surprise, Economy of Force, Maneuver, Unity of Command, Security, and Simplicity were all factors seen during this battle.
Mass is concentrated combat power at a distinct time and place during war. Mass is about synchronizing elements to create the desired result in the most time efficient manner. Mass is required to be quick, decisive, and coordinated in order to create the most efficient attack on the objective or enemy. During the Battle of Inchon, mass was seen when all units, where needed and most efficient, were used to attack Inchon and Seoul. During the initial amphibious attack on Inchon, various regiments were used to attack the enemy. Additionally, the Marine and Army units were able to capture and secure the location in a time efficient manner, capture Inchon in only a few days. Forces were concentrated and focused on certain objectives throughout the Operation. Whether it be on Inchon, the Suwon blocking position, or Seoul, forces were concentrated in order to have the greatest and most effective effect. Through these examples, Mass was seen as a component in the Battle of Inchon.
Objective is the clearly defined, decisive, and attainable target or objective that is the goal for the mission or operation. Objective is also about disrupting the enemy and rendering them incapable of war. This principle can be seen during the two main objectives of Inchon first, then Seoul. Both these were clearly defined objectives with a clear purpose, a clear goal and mission statement. Inchon was a key objective due to its advantageous link and route to Seoul. And then Seoul was key due to the two major supply routes that ran directly through the city. By targeting Seoul and the supply lines, the objective and mission statement was clear and concise. These objectives also clearly disrupted enemy forces by both keeping the enemy busy in battle and also by limiting supplies to the area and throughout the rest of the peninsula. Objective is also a principle that we see as a clear component in this battle through its objective and clear mission end state.
Offensive is the holding, seizing, and retaining objectives by getting decisive results. The goal is to have the enemy react to you based on your chosen actions or attack. Offensive is seen in the Battle of Inchon when Inchon, along with the two major airfields were seized. By seizing Inchon and the key air fields, UN forces were able to hold these key areas in order to maintain the advantage that they wanted. Additionally, once the airfields were secure, they acquired the freedom of action to then send in airlifts and resupplies to help their cause. The attacks on Inchon and capturing the airfields then required the enemy to react to UN actions and to react to the chosen acts they made and initiated. Offensive is seen in the Battle of Inchon through the airfields and attack on Inchon itself.
Surprise is maintaining control in a situation by attacking the enemy when unprepared. Surprise is necessary in order to maintain the advantage during an attack. Surprise requires an attack when the enemy is unprepared. Surprise was evident during the Battle of Inchon in the location choice off the west coast. This area was seen as not being an advantageous location, but nevertheless, General MacArthur picked this because it would catch the enemy unprepared. The enemy never would imagine an attack of that magnitude on the Inchon shores because of the tidal conditions, seawall defenses, and other terrain features. This element of surprise was able to have the enemy off guard and not have enough resources to attack with enough strength necessary. Surprise was a key element that led to the success of Operation Chromite in the end.
Economy of force is about using as little force as necessary to ensure mission success. Economy of force is using the necessary amount of units needed while still having an effective armed forces. All elements need a purpose in order to be used effectively during an operation. Economy of force was used when attacking and recapturing the capital of Seoul. Various units were used in order to effectively have the city surrounded and supported by UN forces. While units all had an essential and clear role in surrounding and capturing the city, units were then moved and used to support other areas that would support the overall mission. This was seen when a regiment of the 7th Infantry Division was ordered to flank around the city in order to support the mission form the south. Economy of force was evident during this battle as units were used as necessary in order to create the most effective result within as minimum force needed.
Maneuver is about creating the most effective movement during an operation that gives them the greatest advantage, protection, and ultimately, the upper hand. Maneuver is about the ability to use flexible combat power. Maneuver was seen in the Battle of Inchon by the movement and maneuver of the units used to flank Inchon, Seoul, and other key locations that were captured. By maneuvering elements to flank around and catch the enemy off guard, UN forces were able to gain the advantage during battle. Maneuver was also seen when entering the Inchon shore and having units coordinate with the tidal conditions, although a disadvantage at some points, it was an advantage later on as units were then on the shores and able to attack the enemy. Maneuver is a component that is seen throughout the Battle of Inchon as well.
Unity of command is about having one commander throughout an operation to ensure clear leadership. Overall, General of the Army MacArthur was the commander of the UN forces during Operation Chromite and create the plan that was then prepared for and executed. General MacArthur was able to lead the UN forces during this time so that they would effectively disrupt the enemy, its resupply, and capture key areas. Furthermore, Major General Almond can be seen as unity of command under the 10th Corps during the 22 day operation. Unity of command was clearly seen during the Battle of Inchon and throughout the Korean War.
Security is about maintaining control of areas, intelligence, and acquiring counter intelligence when necessary. Security is key during battle to ensure success and to maintain the upper hand. Security was maintained throughout the Battle of Inchon in a variety of ways. First, intelligence and reconnaissance was conducted and collected prior to the pre-invasion bombardments. Furthermore, the island off the coast was first secure for friendly units. Security was always the top priority for each of the areas that the UN forces sought to capture. Security was maintained at all times during the Battle of Inchon to ensure that at no point was the upper hand given to the enemy.
The final principle of war is simplicity, which is having a clear, concise, and uncomplicated plan. Simplicity is key so that all elements are able to understand their purpose, and the commander’s intent and end state. Simplicity was seen throughout the Battle of Inchon because of the simple flanking that UN forces would initiate to capture key areas and locations. Simplicity is the ability to create a basic plan that all can understand, which all participating units during the Battle of Inchon understood during that time.
All nine of the principles of war can be clearly seen in the Battle of Inchon. Each principle is key in the planning, preparation, and execution of each element of the battle. Every step had each of these principles in mind and this factor led to the success of General MacArthur and the UN forces. The Battle of Inchon can be seen as a success for the UN forces because of its successful planning and results in capturing Inchon, Seoul, and key airfields and locations. The importance of this battle was not only to capture these areas, but to also ultimately create the opportunity for forces down in the southeast Pusan peninsula to be able to attack back and push the North Korean People’s Army farther north.