Dien Bien Phu: the battle that split Vietnam

By 1953, the French government had faced the inevitable. Starved of men and short of popular support, they were never going to be able to force the surrender of the Viet Minh. It was now simply a case of strengthening their position at the bargaining table. To achieve that end, General Henri Navarre, their new military commander in Indochina, was instructed to improve the military situation in the country.

• Read more in our guide to the Vietnam War

Although Navarre planned to use the bulk of his reserves in a sweep against Viet Minh forces in the south of Vietnam, he realised that the greatest threat to French interests actually lay in the north of the country, especially as Viet Minh forces had moved into neighbouring Laos. Laos had just been granted independence from France, but it remained an ally and Navarre felt he had to defend it, particularly as there was a real danger that the Viet Minh would then head south to threaten Cambodia and southern Vietnam. Navarre had other reasons to be concerned about the north.

The T’ai people of the extreme northwest corner of Vietnam were actually supporters of the French, but their base at Lai Chau was coming under increasing Viet Minh pressure. And then there was opium. The poppy fields of the northwest were a major source of income, which both sides wanted to control: the Viet Minh to raise money to purchase weapons, the French to fund special operations.

Bearing all this in mind, Navarre came up with a plan. French forces would set up a fortified camp in the northwest, which could act as a base for raids and other offensive operations, block the Viet Minh’s supply route into Laos and serve as a new headquarters for the beleaguered T’ai. And if the Viet Minh tried to attack it, so much the better. They would be drawn into a conventional battle in which superior French training and firepower would prove decisive.

Into the valley

For his new base, Navarre selected Dien Bien Phu, a mountain valley with an airstrip, about 300km northwest of Hanoi. In choosing this site, the French made two assumptions. First, that they would be able to resupply their troops there by air and, second, that the steep wooded mountains overlooking the valley would prove an impenetrable barrier for the Viet Minh artillery. They would be wrong on both counts.

On 20 November 1953, the first French troops parachuted into the valley, quickly dispersing the Viet Minh troops in the area and seizing the airstrip. Over the following weeks, a further 12,000 troops would be flown into Dien Bien Phu together with 30 artillery pieces and even a squadron of tanks, which were delivered in pieces and then assembled on the ground.

The commander of the garrison was Colonel Christian de Castries, a swashbuckling cavalryman who Navarre believed would be ideally suited for the offensive operations he envisaged being launched from the base. The French set about fortifying their position by constructing about three dozen strongpoints, which were grouped together into clusters. In true Gallic fashion, each of these was given a woman’s name – Annemarie, Beatrice, Claudine, and so on.

• On the podcast | Christopher Goscha explores the conflict between the French empire and Ho Chi Minh’s Vietnamese army that followed

These strongpoints were rather hastily built and not really secure enough for a protracteds iege, but the French weren’t anticipating such an event. In any case, they were sure that they had nothing to fear from the Viet Minh guns.

After all, Colonel Charles Piroth, the jovial onearmed commander of the French artillery at Dien Bien Phu, had assured them that the Viet Minh would never be able to get their guns up the mountains that overlooked the base. Even if they did, his own guns would destroy them the moment they gave away their position by opening fire. Piroth’s confident words would come back to haunt him; the French had made the fatal mistake of underestimating their enemy.

The Viet Minh commander, General Võ Nguyên Giáp, has been described as one of the greatest strategists of the 20th century. Like the French, the Viet Minh leadership believed that a military victory would strengthen their hand at the conference of great powers that was due to begin in Geneva and it was down to Giáp to deliver such success. Identifying Dien Bien Phu as the place where such a victory could be won, he concentrated nearly 50,000 combat troops in the area, seizing the high ground around the base and surrounding the French garrison.

It was a triumph of logistical planning. To ensure that his troops had the ammunition and supplies they needed to take on the French, Giáp mobilised a quarter of a million Vietnamese civilians to build scores of new roads and construct hundreds of bridges. Civilian porters transported supplies on animals, specially reinforced bicycles and hundreds of Russian Molotova trucks. Dozens of artillery pieces and thousands of shells were laboriously manhandled into position in the hills around Dien Bien Phu and dug into bunkers with trenches and shelters to protect their crews.

By March 1954, Giáp was ready to strike. The ensuing battle has been described as taking place in a stadium with the Viet Minh in the stands and the French on the field, their every move visible unless it was made at night or during the early-morning fog that sometimes shrouded the valley. On 13 March, Giáp stunned the French by unleashing a devastating bombardment on the Beatrice position on the northeast corner of the French perimeter. Beatrice was then attacked by an entire Vietnamese division and fell after several hours of heavy fighting.

Of the 550 Foreign Legionnaires, only a few dozen escaped. On 14 March, the Gabrielle position received the same treatment as Beatrice. By 23 March, both Annmarie and Huguette were in Viet Minh hands and the airstrip was virtually unusable.

The last flight into Dien Bien Phu took place on 28 March. From then on, all supplies had to be dropped in by parachute. Even so, the Viet Minh anti-aircraft fire was so effective that French supply planes were forced to fly at a much higher altitude than they wanted, causing thousands of parachutes to miss their targets and drift into enemy territory. Even the bottle of champagne dropped to mark de Castries’ promotion to Brigadier-General ended up in Viet Minh hands.

Numbers game

These reverses came as a devastating blow for French morale, none more so than for Charles Piroth, who retreated into his bunker to blow himself up with a grenade. Christian de Castries himself seems to have lost confidence in his own ability to handle the battle and passed tactical control over to two hard-bitten French paras, Colonel Pierre Langlais and Major Marcel Bigeard. As time went on thousands of soldiers, mainly Indochinese troops who made up a third of the garrison, gave up fighting altogether and took shelter in the caves that adjoined the river running through the Dien Bien Phu position.

But the Viet Minh were suffering morale problems of their own. Every strongpoint captured, every yard gained, came at a horrific cost in human lives. So Giáp changed his tactics. The mass infantry attacks of March were replaced by a slow but steady approach. It was now classic siege warfare, with the Viet Minh soldiers inching their way in trenches towards the French positions. Meanwhile, the onset of the rainy reason added to difficulties on the ground and made French supply drops from the air even more difficult to carry out.

By May, the French were running out of food, ammunition and hope. The final Viet Minh assault was launched on 6 May and the last French soldiers surrendered the following day. Around 11,000 troops, many of them wounded, marched into captivity. Fewer than half would return home.

Julian Humphrys is a historian and author specialising in battlefields. His books include Enemies at the Gate (English Heritage, 2007)

This article was first published in the May 2019 issue of BBC History Revealed