How did the 1st Marine Division succeed in holding four major strongholds divided and surrounded by volunteers?
The U.S. 1st Marine Division was divided and surrounded by the 9th Volunteer Corps. The operation plan for the Jangjin-ho Battle was as follows: the 59th Division of the 20th Army attacked the Deokdong Pass to the south of Yudam-ri, cut off the connection between Yudam-ri and Hagaru-ri, and attacked Yudam-ri from the south.The division attacked Hagaru-ri from the east, south and west;Division 60 moved north from Khuto-ri, cut off khuto-ri from hagaru-ri, and attacked Khuto-ri from the north;The 89th Division joined forces with the 59th division to attack the enemy in Yudam-ri. The two main divisions were deployed west of Yudam-ri as reserve troops.The 79th Division of the 27th army attacked Yudam-ni from the north;One regiment of the 80th and 81st divisions attacked Xinxingli;The main two regiments of the 81st Division are deployed in the area to guard the first part of the 31st Regiment of the 7th Division and protect the flanks of the army.On the night of November 27, 1950, the battle of Chosin Lake began as planned.According to Song s operational plan, the 9th Infantry Corps will take the first Marine Division to Yudam-ri (approximately 9,000 marines from the 5th and 7th marines) and Hajeuku-ri (3,645 soldiers), but the main forces of the defense are only two companies and two artillery companies of the 3rd Infantry battalion of the 1st Marine Regiment., Gotori (1st Marine regiment 2nd battalion, more than 1000 people), Xinxingli (1st Marine regiment 1st battalion, more than 1000 people) four main strongholds are divided and surrounded, contrary to the expectation that the 9th Corps will soon annihilate the Encircled American troops, the volunteer army attack forces only formed a confrontation with the American troops after a night of fierce fighting,The 1st Marine Division successfully held these four points divided by the volunteers for the remainder of the battle.After the battle of Jangjin-Ho, the U.S. Marine Corps Study Board said that although this phase of the operation was a withdrawal operation, the withdrawal operation was carried out in the face of overwhelming enemy forces. Contrary to normal withdrawal operations, the way the 1st Marine Division conducted the withdrawal operation produced some very important tactical gains.These tactical achievements can be summarized as follows: 1: Through the skilful use of integrated ground and air operations, the 1st Marine Division was able to escape from the trap of overwhelming enemy ground forces with all operational equipment, safely transport the wounded and maintain tactical integrity.2: Confronted the forces of at least seven divisions of the volunteer army under the terrain and weather conditions chosen by the enemy.Although frostbite took a heavy toll on the 1st Marine Division, it hit the volunteer force hard, which was perhaps decisive.3: In the process of completing the second point above, most of the units of the ninth Volunteer Corps were rendered militarily impossible to fight again.Those volunteer units that did not engage the 1st Marine Division were trapped in the Jangjin-ho reservoir area and were thus ravaged by cold weather and heavy air raids.4: As a direct result of the third point above, in the event of a sea evacuation (the most difficult operation), the tenth Army was able to withdraw from Hungnam Port without enemy interference as a combat effective unit with all personnel and available equipment.If the 9th Volunteer Corps had put pressure on the 10th army, it would have changed the result.So, what are the characteristics of the 1st Marine division in terms of defense and offense?American troops in the post-war battle report, according to the training of the 1st Marine division and equipment is to make it as a cohesive, balance of combat forces, mainly to undertake amphibious task, 1st Marine division in battle to use a slightly deviate from the aim of the Korean peninsula, second, because of the tenth army to it and different tasks should be carried out at the same time, it also fell into some groups of chaos.In addition, the 1st Marine Division, which was extensively used in the Inchon-Seoul operation, still failed to regain its strength when it withdrew from the mid-western part of the Korean Peninsula.The 1st Marine Division was not equipped and trained for prolonged land operations far from supplies, nor was it adequately equipped for mountain operations in zero-degree weather.The fact that the Korean War was considered to be drawing to a close did not mitigate the fact that the 1st Marine Division was being used improperly.The 1st Marine Division’s chances of survival depend in large part on the lessons it has learned from the last four weeks of combat operations.Mountain operations and operations under the cold weather is not a Marine corps expertise, but proud of adaptability, the Marine corps and the 1st Marine division group is the first large-scale volunteer unit 7 combat troops, the seventh regiment combat brigade had hit a division of volunteers, but the result is far more profound for new operational methods of evaluation of the enemy.Colonel Lizberg, commander of the 7th Regiment, not only studied the tactics of the volunteers, but also tried new Marine tactics to deal with the volunteers.In all four attacks, from Hamhung to Yudam-ni, the 7th Marine Regiment effectively became a constantly mobile tactical laboratory.According to us military observation, the tactics of the volunteers were very good at dispersive forces, and one of the main objectives of the volunteers’ night raids was to create conditions for this purpose, by breaking through to cut off a platoon or even a company of outposts.Cohesion is the answer to the volunteer tactic. Cohesion is the best way to use the superior firepower of the American army. Therefore, the Marines are always organized into units that can withstand sudden attacks from the front, side and rear, which means moving like a fortress in a tight ring.In any case, experience has taught us that a regiment’s position should be organized at a minimum depth of 3,000 yards and at a maximum depth of 5,000 yards to provide full protection and mutual support.Patrols made up of reinforced companies were rarely sent out of range to support fire.The 1st Marine Division prioritized defensive depth and solidarity with local troops in its four main positions, Including Ryudam, Hagaryu, Goju-ri, and Jinheung-ri, occasionally abandoning high ridges close to the enemy in order to strengthen its defensive line.At any time, the troops are all in their own defense operations in the form of fort, launch a counterattack to overbalance the volunteers, to defeat the enemy on the ground should not gain the advantage of the position selection of circular arc, the abandoned can take advantage of firepower vast terrain surface, choosing instead to make the defenders can achieve maximum mutual support in the line positions.The 1st Marine Division did not choose positions that could effectively kill the enemy at a distance. Instead, it built defenses that could stop volunteer attacks at short distances while still holding its own position without overspreading its forces.Instead, positions were shrunk to the point where local reserve forces could be mobilized.In the initial battle, the position at Hagaru-ri might have been an example of this rule, as there were very few troops there, and the terrain had to be taken into account, with a large airstrip in the sector.However, service and administrative personnel, local reserves were used to fill gaps in the lines and respond to emergency situations arising from volunteer attacks.Defensive characteristics The 1st Marine Division used outposts and guard positions outside its defensive lines, although this practice varied from base to base, depending on the opinions and circumstances of the local commander.Establish a perimeter 200 to 300 yards in front of the line so that the enemy cannot attack by surprise.The troops usually find the attacking volunteer within 40 to 150 yards. The volunteer shouts in English as he receives the enemy, and the AMERICANS fire at the source of the sound.The U.S. 1st Marine Division, which is on patrol, will actively patrol the main routes approaching the positions during the day.Although these patrols were trying to gather intelligence on the enemy, their main purpose was that the 1st Marine division, knowing that it was under constant observation by volunteers, was trying to impress the enemy that the 1st Marine division was active.The strength of these patrols is usually a company and sometimes an enhanced platoon.Depending on the conditions and the purpose of the operation, the patrol would travel by car or on foot, usually no more than 1,500 yards, but at Liutam, the farthest patrol was five miles from the line and always within artillery cover.Artillery observers were accompanied and, where possible, an observation aircraft was sent to assist patrols in their observation and communication with bases.The 1st Marine Division believes that as a result of its aggressive patrols, its main base has never been harassed by small groups of volunteers during the day.According to the combat system of the 1st Marine Division, platoon and company leaders direct heavy weapons fire to prepare and conduct combat, and they rely on support weapons centers, which conduct fire planning at the battalion level.Basically, the Support Weapons Center coordinator is the assistant to the operations staff and is responsible for fire planning for both offensive and defensive aspects. Normally, he works at the battalion headquarters;During the perimeter, his post was in the operational staff’s tent.During the organization of the defense, he assisted the operational staff in preliminary reconnaissance;It gave him a chance to familiarize himself with the front lines, to spot the heavy machine guns and to note the enemy’s attack routes to be covered with artillery and mortar fire.When the reconnaissance is complete, the front line is mapped on the battle map.Mortar and artillery officers were told what fire to carry out.Fire operations were carried out by their operational officers;When the recording is complete, the information is forwarded to the support Weapons center and the fire concentration points are depicted on the situation map.In addition, when the patrol is out, the support weapons center will mark their position for quick artillery fire.Usually, the support weapons Center coordinator is an infantry officer.He is in close contact with tactical Air Control so that coordination will be immediate and complete when the target of his weapon attack is also suitable for air attack.The battalions of the 1st Marine Division felt that their support artillery was very effective, thanks to improvements in the support weapons Center.Characteristics of the U.S. 155mm self-propelled howitzer offensive The main feature of the 1st Marine Division offensive is that it is very carefully coordinated and synchronized with all weapons in order to support rifle companies or rifle battalions to gain position with minimal cost.In a typical case, rifle companies would be temporarily halted by heavy automatic weapons fire from high ground, and the volunteers would tend to dig defensive bunkers on the hilltops in an attempt to distract the AMERICANS from volunteer automatic weapons positions in saddle terrain, where the American infantry companies would hold positions and call for mortar fire support.At the same time, or immediately after the mortar fire, the volunteer position and the ridge behind it were subjected to artillery bombardment.Close air support by U.S. aircraft several aircraft would be called in at the same time, and after the bombardment, the aircraft would strike the volunteers for the first time.After the aircraft attack or depending on the distance to the volunteer position, the American infantry attack or begin advancing toward the volunteer position for a final attack.The infantry units of the 1st Marine Division received very good artillery coordination, a typical operational procedure with only a few exceptions during the Battle of Chosin Lake.Attacks at company, battalion and regiment levels were carried out in this manner.Because of their different trajectories, a combination of multiple fires can certainly kill more enemies than a single fire support.