Over half a century ago, to realise a strategic diversion action in preparation for the General Offensive and Uprising of 1968 throughout the South, we launched a large-scale combined arms offensive campaign at the Khe Sanh - Route 9 and achieved a great victory. The Campaign left behind valuable experiences in military art, among which the distinct feature was the art of encircling and cutting off the enemy.

After a series of consecutive failures of the “search and destroy” and “pacification” tactics during the dry season of 1966-1967, the "Limited War" strategy of the US was on the brink of complete failure. The US found itself in a passive strategic position, forced to shift to defence and focus on protecting key areas, including the strategic defensive line of Route 9 - Khe Sanh. To implement this plan, the enemy concentrated forces and resources, constructing a strong defensive zone in the Route 9 - Khe Sanh area with a robust system of interconnected fortifications, equipped with modern and advanced weapons and equipment. Additionally, maximum fire support was provided by the US Air Force, artillery, and other combat elements.

The enemy's C130 transport aircraft was shot down at Khe Sanh base

On our side, by the end of 1967, recognising the emergence of a “new strategic” opportunity for the revolution in the South, the Central Party Committee and the Politburo made the decision: “Shift the revolutionary war of our people in the South to a new period, a period of decisive offensive and uprising”. In accordance with this decision, we launched the offensive campaign in Route 9 - Khe Sanh, implementing a strategic surprise attack to lure and bog down the enemy’s main forces in the Route 9 area. This was coordinated with our general offensive in major cities, particularly the direct assault on Hue, while simultaneously destroying a significant portion of the enemy’s strength (primarily the US troops) and breaking through their interconnected defensive lines. With the correct guidance and close direction from the Party, the Central Military Commission, and the Ministry of National Defence, along with the high determination and fighting spirit of our forces, and the creative application of the people’s war military art in each area, the Route 9 - Khe Sanh Campaign was a great success. This victory marked a new development in Vietnam’s operational arts, showcasing the distinct features of the art of encircling and cutting off the enemy.

First, accurately select the area and targets for encirclement and cut-off actions. To implement the combat principles of the Campaign, which prioritised engaging the enemy outside their fortifications and, when necessary and with a high chance of success, attacking entrenched enemy, combining small-scale, medium-scale, continuous, and widespread attacks to create opportunities for large-scale offensives, the Campaign Command had to make the precise choice of the area for encirclement and cut-off actions – “point encirclement”. This would force the enemy to carry out rescue and relief operations, exposing their formations, forces, and resources outside their fortifications, thereby enabling our force to carry out attacks to destroy a large number of enemy troops - the “destruction of enemy reinforcement”. Accordingly, the Campaign Command focused its forces and resources on the offensive in the districts of Huong Hoa, Huoi San, and Vay Village, establishing a solid posture for the encirclement of Ta Con. The selection of Ta Con as the location for encirclement and cut-off actions demonstrated the insightful, sharp, innovative vision and analytical capabilities of the Party Committee and the Command of the Campaign. Ta Con was situated in the centre of the Khe Sanh Valley and served as a vital link in the “McNamara Line,” an important electronic barrier that formed a solid interconnected defensive system for the enemy. The US military hoped to use these bases as a “shield” to control and prevent the strategic support from the North to the South, particularly from Laos, and to counter our offensives from the North. They also used these bases as launching points for “hopping” operations to search and destroy our main units. Additionally, Ta Con was the anchor point in the northern section of Route 9, with Ta Con airfield serving as the logistical hub for the enemy, receiving reinforcements, weapons, and supplies. It was the centre of the enemy’s defensive system in the western direction, organised with relatively strong forces and combat systems. With such strategic significance, once Ta Con was completely encircled and faced the risk of annihilation, the enemy was compelled to deploy significant forces to rescue and relieve this base, providing us with an opportunity to launch an offensive to destroy them outside their fortifications. Furthermore, the complete encirclement and isolation of the Ta Con complex would impose an operational division on the enemy battle order, cutting off an important link in their western defensive line, completely breaking their interconnected defensive positions and significantly reducing their ability to coordinate their defence. The mountainous and forested terrain of the area limited the enemy’s advantages in firepower and mobility, allowing us to employ our combat forte and carry out the tactic of “divide the enemy to fight them, tie down the enemy to destroy them”. Therefore, despite the enemy’s four counterattacks launched against Ta Con during the encirclement, they were all defeated by us. Meanwhile, they continuously deployed forces for rescue and relief operations by land and air, even deploying the prestigious US 1^st Cavalry Division in the 3^rd phase, but they still could not reverse the situation. As a result, the campaign achieved its strategic objective of luring and bogging down the enemy’s main forces towards Route 9, forcing them to carry out rescue and relief operations, and exposing their forces and combat systems outside their fortifications, thereby creating an opportunity for our offensive to destroy them.

Second, utilise appropriate forces to conduct encirclement and cut-off actions. By establishing a strong base in the Khe Sanh valley, the enemy intended to lure our main units to this area and create a symmetrical battle array, then utilise the air superiority, particularly with B-52 bombers and artillery firepower, combined with elite forces, aiming to turn the area into a “second Dien Bien Phu” to “crush” our main forces. Understanding the enemy’s intentions and tactics, with unique military art, particularly the art of appropriate force utilisation, we organised a complete encirclement and isolation of the Ta Con complex, cutting off the enemy’s defensive line from Cua Viet to Lao Bao. We organised forces to launch offensives and destroy the enemy’s rescue and relief operations, successfully implementing the art of “point encirclement” and “destruction of enemy reinforcement.” During the Campaign, we used the 325^th Division to encircle the enemy in the north and northwest directions, and the 304^th Division to encircle the enemy in the south of Ta Con. The distinct feature was that we did not create a symmetrical battle array with the enemy, nor did we concentrate large forces for encirclement. Instead, the divisions only employed small contingents of battalion and company levels to break down enemy formations, and combined these units with artillery firepower, to “stick with the enemy to fight them”. We created an “interwoven” battle order with the enemy, flexibly transitioning from encirclement to encroachment, approaching the enemy’s defensive perimeter. At several points, we were able to breach their defensive line and even make breakthroughs in their perimeter, causing huge pressure upon the enemy forward positions, dividing and threatening the enemy forces defending the complex. Meanwhile, the main forces were positioned outside in strategically valuable positions, constructing defensive fortifications, ready for mobile operations to engage the enemy’s rescue and relief forces. Thanks to the appropriate use of forces, especially during the 2^nd phase, the 304^th Division ordered the 9^th Regiment to rotate its battalions in the encirclement, while the 24^th and 66^th Regiments were on standby, ready to engage the enemy’s rescue and relief forces in the south and southwest of Ta Con. As a result, we were not only able to limit casualties caused by the enemy’s firepower but also defeat their tactics and combat measures. Additionally, the Campaign Command ordered artillery strikes against Ta Con airfield and the enemy’s artillery batteries, inflicting casualties on the enemy, damaging their fortifications, positions, and vehicles, and disrupting aerial resupply operations, placing them in an increasingly desperate situation with diminished combat capability and morale, leading to their inevitable defeat.

Third, flexibly and creatively apply various tactical forms and fighting methods, continuously encircling and dividing the enemy. To effectively carry out encirclement and cut-off actions, defeat enemy counterattacks, and be ready to manoeuvre to destroy the enemy’s rescue and relief forces, the Campaign Command employed flexible tactical forms and fighting methods to limit the enemy’s strengths, exploit their weaknesses and maximise our capability and forte. This included seizing the initiative, establishing and transforming the battle array flexibly and timely handling various contingencies to accomplish assigned tasks. To establish a springboard for the encirclement and isolation of Ta Con, we organised offensives against the enemy’s defensive positions in the districts of Huong Hoa and Huoi San. Specifically, we utilised the combined forces of infantry and armoured units to attack the fortified position of Vay Village. We also utilised artillery firepower to control Ta Con airfield and intensify the disruption of traffic along Route 9, specifically from Ku Boc to Rao Quan, completely cutting off and isolating Ta Con by land. However, the pressure on Ta Con was not strong enough, so in the 2^nd phase, the Command of the Campaign decided to transition from encirclement to encroachment, forcing the enemy to deploy large forces to rescue and relieve this base. They even had to employ the 1^st Cavalry Division, their most powerful mobile force, in an attempt to rescue their main units that were trapped in the Ta Con area (relief operation). Recognising the enemy’s intentions and tactics, when the forces inside the stronghold tried to break out westward to loosen the encirclement, the 66^th Regiment launched a surprised assault against the enemy’s formations, successfully annihilating an entire enemy marine infantry company, defeating their plan, and maintaining pressure on Ta Con. Thanks to the flexible application of tactical forms and fighting methods, along with the effective encirclement and division of the enemy, we actively “manipulated and lured the enemy” using our own methods, forcing them to conduct rescue and relief operations with increasingly larger forces. This created an opportunity for the 308^th Division (the mobile force of the Campaign) to coordinate with artillery and local armed forces, timely transform the battle array, and organise an offensive to destroy the enemy’s airborne forces that aimed to rescue and relieve the encircled enemy units in areas such as Ta Ri, Ta Quan, Pa Trang, Huc Cot, and others. Despite the enemy’s deployment of a large, battle-hardened force and their advantages in aerial firepower, artillery, and modern electronic warfare, we maintained a favourable battle array, continuously encircled and isolated the enemy, established a favourable battlefield situation, and provided favourable conditions for our forces, especially the mobile ones, to launch offensives and destroy the enemy’s forces outside their fortifications. This forced the enemy to withdraw from the Khe Sanh area, ultimately bringing the Campaign to a successful conclusion.

The valuable lessons and experiences in military arts, including the art of encirclement and cutting-off action against the enemy in the 1968 Operation Route 9 - Khe Sanh, need to be further studied and creatively applied in the cause of national defence today.

Senior Colonel, MSc. PHAM DUC TRUONG, Military History Institute