Combined Arms in Battle Since 1939

Lieutenant Colonel James R. McLean

The village complex of Dien Bien Phu lies in the center of a large valley in northwestern Vietnam approximately 180 miles from Hanoi. This rich, fertile valley is some 12 miles long and 8 miles wide and is completely surrounded by tall, jungly mountains whose peaks rise to over 3,000 feet in many places. By 1953, the village had served as an administrative center for the Vietnamese government for over seventy years, being an important marketplace for two important local cash crops-rice and opium. An important regional crossroads, it sat on Provincial Road 41, the major north-south highway in the area, and controlled Vietnamese access to Laos, only eight miles to the west.

Opposing the French were Vietnamese Communist nationalists under the leadership of Ho Chi Minh. Ho had organized the Vietminh to oppose Japanese occupation forces during World War II and continued to lead them against France when that country attempted to reestablish colonial rule in 1946. His goal was to create a unified, independent Vietnam under his leadership. The senior Vietminh commander was Vo Nguyen Giap, a former history teacher and long-time supporter of Ho Chi Minh. With the cessation of hostilities in Korea, the Chinese Communists were able to provide increasing military assistance and hardware to their allies to the south. Given this new level of aid, Ho and Giap sought to go on the offensive against the French and drive them from Indochina.

In the summer of 1953, Navarre had 189,000 troops in Indochina: 54,000 French soldiers, 20,000 Legionnaires (many of whom were German or Eastern European), 30,000 North Africans (Algerians and Moroccans), 10,000 air force and 5,000 navy personnel, and 70,000 members of the Vietnamese National Army. Most of these were needed to man garrisons throughout Indochina, particularly along a chain of defensive positions in the Red River delta called the De Lattre Line. The Vietminh, with 6 divisions and 3 independent regiments, had at least 80,000 well-trained first-echelon soldiers, along with a large body of second-echelon militia available for regional conflicts and activity. These, in turn, were backed by large portions of the peasant population whose support the Vietminh had already won.
Navarre's long-term plan for defeating the Vietminh envisioned limited offensive operations by his regulars to keep Giap's forces occupied while the French rebuilt the Vietnamese National Army in 1954. Then, in 1955, he would mount a general offensive to destroy Ho Chi Minh's People's Army of Vietnam (PAVN). Prior to Navarre's arrival in country, the French had achieved some success against the Vietminh by creating forward operating bases behind enemy lines. An airhead, seized by an airborne insertion, would be rapidly expanded by airlifting in artillery, engineer, and support elements, as well as regular infantry units to replace the paratroopers. The French then would conduct limited local offensive actions disrupting the Vietminh rear and causing PAVN units to attack their positions in force. Next, the French would use the inherent strength of the defense and their superiority in firepower, both artillery and air support, to inflict heavy losses on their opponents. When this was accomplished, the operation would terminate, and the entire French contingent would be withdrawn by air.
The key to this kind of operation was to choose a provocative site, man it with sufficient forces to prompt the enemy to attack (and thus accept an attrition battle), and then retain the ability to withdraw the force when necessary. The French had employed these successful tactics before Navarre's appearance. Navarre now intended to intensify these tactics and expand their scope. In the autumn of 1953, Navarre selected Dien Bien Phu as the centerpiece for his plan to engage the Vietminh in northern Vietnam.
On 20 November, elements of the 1st Airborne Battle Group jumped into Dien Bien Phu. Within two weeks, nearly 5,000 French troops were in the valley, improving two airstrips and building defensive positions. Navarre's trap was set. The bait was six battalions of airborne infantry, the cream of the French Army in Indochina.
Ho and Giap carefully analyzed the situation before accepting battle. They determined that the French strength was in fire support, both artillery and air power, and that the French weakness lay in their extended and vulnerable lines of communication (LOCs). The Vietminh leaders also considered their own position and identified their strengths as their skilled infantry and the support of the people. Their weaknesses were their lack of firepower and their inability to sustain large-scale conventional operations. Therefore, the Vietminh leaders decided that victory at Dien Bien Phu would depend on their ability to reduce the effectiveness of French fire support and to sever the enemy's lines of supply while, at the same time, reinforcing their own firepower and protecting their own LOCs. Less than a week after the first French paratroopers jumped into Dien Bien Phu, Giap ordered four divisions to converge on the valley, to arrive no later than the end of December: the Vietminh had accepted the challenge.
The French military's analysis of the centers of gravity for the Dien Bien Phu campaign was fatally flawed by its overestimation of French capabilities and its underestimation of the Vietminh's. Like Ho and Giap, the French realized that the keys to success or failure would be logistics and fire support. The French fully respected the prowess of the PAVN infantry but felt confident that superior French air and artillery support would more than offset any numerical advantage the Vietminh might muster. Furthermore, the French believed that the Vietminh could neither mass nor sustain the forces necessary to overcome the garrison at Dien Bien Phu, and if they attempted to, French air power would smash their LOCs and pound their assembly areas. A combination of offensive maneuver and artillery and air support would prevent the Vietminh from interdicting French aerial resupply operations at the two airfields in the valley.
Navarre and his operational commander in northern Vietnam, Major General Renï¿½ Cogny, felt that the French Air Force would be able to locate and cut any Vietminh supply routes into Dien Bien Phu. However, during the operation, the French flew hundreds of reconnaissance and battlefield air interdiction sorties against the enemy LOCs and were not effective. Expert use of camouflage, movement at night and during periods of limited visibility, use of redundant routes, creation of extensive engineer repair systems to build and quickly repair the elaborate road network, the use of more than 500 21/2-ton trucks given by the Chinese, and the mobilization of tens of thousands of peasants to provide manual labor and to carry thousands of tons of supplies all helped defeat French efforts to cut the supply lines sustaining the Vietminh army.
The French also grossly underestimated the fire support capabilities of their opponents. Colonel Charles Piroth, the commander of all French artillery at Dien Bien Phu, insisted that the Vietminh could bring neither large quantities of artillery nor the amount of ammunition necessary to sustain effective operations into the area over the extremely rugged terrain. He was wrong on both accounts. The French felt that Giap's forces could field only 40 to 60 artillery pieces with fewer than 25,000 rounds of ammunition. In fact, Giap brought well over 200 guns to bear during the battle and fired over 350,000 rounds. Because the French had dismissed the Vietminh artillery threat, they did not adequately prepare their positions to withstand the heavy artillery bombardments that characterized the battle. Accurate, concentrated Vietminh fires and the lack of French overhead cover and deep bunkers especially over critical airfield installations and artillery gun pits, contributed to heavy French losses early in the campaign.
In addition to their other miscalculations, the French overestimated their ability to locate and destroy any artillery the Vietminh brought to bear. Piroth repeatedly boasted to high-ranking civilian and military officials who visited the valley in the months before Giap's attack that his counterbattery fires would destroy any Vietminh gun that fired three rounds. Furthermore, several times, he turned down offers to have more artillery sent to the valley, claiming that he already had more than he could use. He based his claims on the belief that the firing of enemy guns could easily be spotted-either directly from ground observation posts or from light observation aircraft that were permanently stationed at Dien Bien Phu-since the weapons would be emplaced on the forward slopes of the surrounding hills. In reality, the hills were too far away for direct observation. Moreover, the Vietminh had learned valuable lessons from their Chinese advisers on how to protect key installations and supply routes from air interdiction. Camouflage was used expertly to hide positions, while dummy positions drew French efforts away from actual locations. Also, some units were moved nightly to lessen the chance of detection. The PAVN forces emplaced their artillery pieces individually, often digging them deeply into hillsides so that they were impervious to all but direct hits.
In contrast to the French, the Vietminh realistically appraised centers of gravity for both sides. Three of the divisions Giap sent to Dien Bien Phu were elite infantry units built on the Western model of three regiments of three battalions each. Although each PAVN battalion possessed more riflemen, machine guns, and heavy mortars than its French counterpart, French overall superiority in artillery and air support more than made up the difference in firepower. But by 1953, the Vietminh had created a unit designed to redress this inequity-the 351st Heavy Division. Modeled after the Soviet artillery division that had time and again provided massive firepower to smash through German defenses during World War II, the 351st consisted of engineer, mortar, rocket, antiaircraft, and field artillery battalions and was manned by the bulk of PAVN soldiers trained in these skills. The 351st's impact at Dien Bien Phu was enormous.
Giap deployed the assets of the 351st Division to protect his LOCs-his weakest link-and to counter the French superiority in fire support. His deployment of nearly 100,000 troops to this remote and inhospitable location and their sustainment during six months of intense siege warfare was a Herculean task. To protect their LOCs, the Vietminh placed antiaircraft artillery (AAA) elements at every choke point the French could attack from the air. These "flak corridors" took such a toll on French fighter-bombers that the pilots were forced to change their tactics by flying faster and dropping their, ordnance at higher altitudes, both of which significantly decreased the effectiveness of the French air campaign. Almost every airplane that flew against the Vietminh LOCs was damaged to some extent, and the French simply did not have the equipment, spare parts, and maintenance personnel to repair or replace them all. Consequently, as early as 26 December 1953, French air commanders diverted attack aircraft to fly flak-suppression missions. Yet despite the maximum efforts of the French air arms-both air force and navy-at interdiction, supplies continued to flow in sufficient quantities to sustain Vietminh combat operations.
The Vietminh did not employ their AAA in a defensive role only. They also used it offensively to attack the French center of gravity, the tenuous aerial resupply system at Dien Bien Phu. The Vietminh quickly surrounded the French with a ring of antiaircraft guns, mortars, and artillery, which they continued to strengthen as more weapons arrived in the battle zone. Consequently, it became increasingly difficult for the French to approach the valley by air due to the concentrated AAA fires. Once the Vietminh began their assaults and forced the French back, the PAVN leaders immediately ordered their 37-mm and .50-caliber AAA guns even closer to the airfield. This ring of AAA hindered French resupply efforts and helped protect the massed infantry divisions and support troops from the French Air Forces' napalm and bombing runs, thus further degrading French fire support effectiveness.
Giap and his planners did not forget the airfield itself and made denial of its use by the French a primary objective for both ground maneuver and indirect fires. PAVN mortars and artillery interdicted airfield operations early by targeting the control tower, radio beacon system, aircraft repair and refueling facilities, observation planes and fighter-bombers parked on the flight line, and the airstrip itself. From December 1953 through March 1954, fewer and fewer aircraft landed at Dien Bien Phu. When Giap at last attacked on 13 March 1954, the PAVN artillery effectively shut down the airfield. Resupply then had to be accomplished by parachute. Initially, the French C-47s dropped their cargo in daylight at 2,500 feet, but as Vietminh AAA gunnery improved and they brought their guns closer to the drop zones, the drop altitude rose first to 6,500 feet and then later to 8,500 feet. Naturally, the accuracy of the drops decreased precipitously, as did the percentage of tonnage actually recovered by the French. Distribution of those items the French did recover was made extremely difficult because the enemy could sweep the drop zones and French positions with fire at will.
Once the battle was joined, both sides used their fire support assets to great effect. The French had built their defense around a series of mutually supporting defensive positions with interlocking fields of fire designed to protect the main airfield in the center of the valley. Each of the artillery pieces had already fired at a number of critical targets, and the Vietminh suffered heavy casualties whenever they stormed a French position. The French gunners and mortarmen were highly trained professionals, possessed the finest equipment in the theater, and were as confident as their leaders that their fires would quickly smash the Vietminh artillery and infantry.
Yet the fire support advantage went to the Vietminh. Before the fighting began, Giap wrote in the PAVN training manual drafted specifically for Dien Bien Phu that the Vietminh needed a minimum 3-to-1 superiority in infantry and at least parity in artillery in order to defeat the French. He had surpassed these ratios when he initiated his offensive on the evening of 13 March 1954. Nearly three and one-half infantry divisions plus the 351st Heavy Division ringed the French garrison in the valley. A total of 49,000 combatants (and a further 10,000 added as replacements later in the siege) opposed the French colonial troops, which although reinforced to 12 battalions still numbered only 13,200, of which no more than 7,000 were first-line soldiers. Of particular importance was how Giap planned to employ his artillery. He knew that he lacked the trained observers, fire direction personnel, cannoneers, and sophisticated signal equipment necessary to operate in the traditional Western mode using indirect fires. However, he held dominant high ground only a few kilometers from his enemy's front lines. Given these factors, Giap came up with an innovative solution to provide accurate and timely fire support. He positioned all his artillery pieces on the forward slopes of the hills so that they looked directly down on the French, and he instructed his artillerymen to fire every piece independently, if need be, by sighting down the tubes of howitzers or by using the direct-lay technique for mortars. This practice helped compensate for the inexperience of many of his men in the use of proper siting techniques. While Giap sacrificed the ability to lift, shift, and mass fires rapidly, he made the most of his assets. Each artillery piece was responsible for a limited sector and was prepared to fire on key targets within its zone. When incorporated into Giap's carefully planned and coordinated attacks, the effects of the Vietminh fires were devastating.
Giap delayed launching his assault on Dien Bien Phu until he had adequate stockpiles of ammunition of all types, his troops were sufficiently trained, and the monsoon season had arrived. The valley of Dien Bien Phu received more rain-almost five feet-than nearly any other valley in northern Indochina during the six-month monsoon season. Giap counted on the heavy rains and low cloud cover to hamper French air support and aerial resupply during this most critical phase of the operation.
At 1700 on 13 March 1954, the Vietminh struck (see map 13). Concentrated barrages laid down by 105-mm and 75-mm howitzers and 120-mm mortars crashed onto the airfield and strongpoint Beatrice with pinpoint accuracy. While some of the PAVN artillery fired on the French infantry positions in support of the assaulting Vietminh, entire batteries that had remained hidden from French detection rained destruction on the open gun pits of the French artillery. Within eight hours, the control tower and radio beacon were destroyed, and airfield operations were effectively shut down. Of the light observation aircraft and fighter-bombers assigned to the airfield for local air support and artillery spotting, only two managed to take off and fly to Hanoi. The rest were destroyed on the ground, thus eliminating much of the French counterbattery potential. By the evening of 15 March, two more French strongpoints, Anne Marie and Gabrielle, had been overrun.
The French were stunned. They had considered Gabrielle to be the strongest of all their fortifications at Dien Bien Phu. Colonel Piroth, the confident one-armed artillery commander, could not believe what had transpired in the previous forty-eight hours. His crews had taken terrible losses in their open gun pits. He had lost two of his 105-mm howitzers, a quarter of his 155-mm howitzers, and a third of his 120-mm mortars to PAVN artillery, and he had fired over 25 percent of his total 105-mm ammunition. As far as he could tell, his cannoneers had had only negligible effects on the Vietminh artillery. He fell into despair and went from one command post to another under heavy fire to apologize for the failure of his command. With tears in his eyes, he said: "I am completely dishonored. I have guaranteed ... that the enemy artillery couldn't touch us-but now we are going to lose the battle. I'm leaving." Later, Piroth went into his dugout and laid down on his cot. Pulling the pin from a hand grenade with his teeth, he held the explosive charge to his chest and committed suicide.
The siege of Dien Bien Phu lasted another fifty-three days. The outcome, however, was clear once the Vietminh had closed the airfield and had revealed the amount and power of their fire support. The French appealed desperately to the United States for immediate massive air support, to include tactical nuclear weapons-but to no avail. On 7 May 1954, the exhausted French stopped fighting, and the victorious PAVN troops swarmed over the last French positions. On the next day in Geneva, France's foreign minister asked for a cessation of hostilities in Indochina, a prelude to coming to terms with the Vietminh. The victory at Dien Bien Phu belonged to Vo Nguyen Giap and was due, in no small part, to his keen analysis of the centers of gravity for both sides and to his brilliant employment of fire support assets to achieve military success.
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