For context: Dien Bien Phu was a battle between France and the Viet Minh. It was the decisive battle of the First Indochina War. During the battle, the French established a base of operations around an airstrip built on a valley floor. The Viet Minh occupied the heights around the French, and then shelled the French into oblivion.
It just seems like the terrain is so obviously vulnerable. Surely the French would have been wise on that, right? Why would the french not occupy find a more defensible position?
Jawbr8kr, that is a really good summary. I am currently reading the Last Valley by Martin Windrow which is very comprehensive regarding units, dates and times.
In addition to your comments: Other key factors in deciding the outcome where:
Lack of Engineering resources: Because the French underestimated the Viet Minh's ability to move offensive support weapons into range of the airfield, Engineering resources to build overhead protection (harbour hardening) was severely under ordered. Furthermore, the number of Sappers in a natural French Battalion were in inadequate supply. As a result, normal infantry and paratroopers were used to build up the position. This resulted in poorly sited trenches and machine gun pits. This made the vulnerable to being cut off and made them less effective in defending the position.
Lack of Logistic capacity. In addition to the Point 1, the required amount of engineering material (bulldozers, concrete, steel reinforcement) would need to be flown in on a constant basis (at the expense of other supplies) which simply could not be achieved given the size of the air field, available aircraft, operational tempo at DBP and other operations at the strategic level.
Training. The French use a very composite force. The garrison was manned not only by French, but by the Foreign Legion, Thais, Vietnamese, Moroccans, West Africans, etc. As a result there was a large variance in the quality of what each unit could produce. This meant that some of the highly trained forces were overworked.
Thoughts?
I understand this is a bit late, but if you are still curious I can answer your question. The French never deployed enough troops to secure the high ground, and because of strategic errors considered it unnecessary.
Actually the French never had enough troops committed to occupy by the valley itself, much less the surrounding heights. The internal perimeter of the valley was about 50 miles long, which meant appox. 58 battalions would be required to securely defend it (1 Battalion = 1,500 yards of front). The French determined to cover a radius of 8km around the airfield, meaning a circular front of 31 miles requiring 36 battalions. However, General Henri Navarre, in charge of all of Indo-China, never considered Dien Bien Phu to be a decisive battle and was conducting an entirely separate Operation Atlante in South Vietnam at the same time. General Rene Cogny, commander of the forces in the North including Dien Bien Phu, was opposed to the operation at Dien Bien Phu from the outset and was extremely unwilling to commit troops he wanted for the Red River Delta region. In the end Dien Bien Phu was initially allocated 6 Battalions; about 5.000 combat troops. These troops were deployed to both defend the airfield (the lifeline for the valley) and conduct offensive operations in enemy rear areas, (not to fortify and defend the valley itself). When it became obvious that Dien Bien Phu would have to withstand an assault, the number of deployed troops increased to 9 Battalions along with additional artillery (though not nearly enough). Meaning that in the end the French sought to defend an isolated mountain valley with about 25% of the troops required for the operation (9 out of 36 battalions).
Obviously when examined like this, the entire plan seems ridiculous, bordering on negligent. Especially when the French intelligence knew as early as December 1953, that the Viet Minh were massing at least 3 divisions (ended up with 5 including the 351st Heavy Division, a dedicated artillery formation) in the area around the valley. However, the Battle of Na-San the year prior had shown that entrenched French troops backed by artillery and air support could successfully resist a Viet Minh assault. This outcome, along with known Viet Minh inexperience at assaulting fortifications, and assumed artillery and air superiority meant the French believed their strongpoints could fix the Viet Minh light infantry, which could then be smashed with overwhelming firepower.
At Dien Bien Phu though The French significantly underestimated the Viet Minh’s ability to deploy and supply their own troops and artillery to the valley. Dien Bien Phu is in an extremely remote area and French leaders believed it would be impossible for the Viet Minh to deploy artillery (greater than 75mm caliber) across the inhospitable jungles and mountains. this proved to be dramatically wrong. Not only did the Viet Minh deploy almost 5 times as many artillery pieces as the French, they were adequately supplied to fire throughout the battle, and French counter battery was so ineffective the French Artillery Commander in the valley, Col. Piroth, committed suicide in disgrace just a few days into the siege.
So: the French did not intend for Dien Bien Phu to be a fixed decisive battle and thus did not allocate enough battalions to its defense. When it became clear a fixed battle was imminent they radically miscalculated their advantage in firepower, and mistakenly believed this false advantage could overcome their poor positioning and weaker numbers.
Let me know if you have anymore questions, or you want me to cite specific pages. My source for this is Hell in a Very Small Place: The siege of Dien Bien Phu, by Bernard Fall, 1967.