"The impregnable fortress"

Việt Nam•07/04/2024

"To gain the initiative, we must occupy Dien Bien Phu." With that ambition, the French colonialists decided to build Dien Bien Phu into "the strongest fortified complex in Indochina" - an impregnable fortress, hoping to crush the fighting spirit of our army and people.

The impregnable fortress The A1 hill stronghold (a model is displayed at the Dien Bien Phu Historical Victory Museum).

Dien Bien Phu is a vast valley in the western mountainous region of Northwest Vietnam. According to many French military strategists, Dien Bien Phu “is a strategically important location not only for the Indochina battlefield, but also for Southeast Asia – a transportation axis connecting the borders of Laos, Thailand, Burma, and China.” It was “a key to protecting Upper Laos,” a “pivot” that could rotate in four directions: Vietnam, Laos, Burma, and China. Dien Bien Phu was also the largest, most populous, and wealthiest plain in Northwest Vietnam. “The rice from this region could feed 20,000 to 25,000 people for many months.” From Dien Bien Phu, the French army “could protect Laos, and from there recapture lost territories in Northwest Vietnam in 1952-1953 and create favorable conditions to destroy the enemy's main divisions if they arrived there.”

Understanding the strategic importance of Dien Bien Phu, on November 20, 1953, Navarre, Commander-in-Chief of the French expeditionary forces in Indochina (since May 1953), decided to launch Operation Castor, a parachute attack to occupy Dien Bien Phu. After dropping six mobile battalions along with a large quantity of ammunition, food, and war equipment into Dien Bien Phu, the French immediately began constructing fortifications and conducting offensive operations to open a land route connecting Dien Bien Phu with Lai Chau and Luang Prabang (Laos).

On November 25, 1953, the French High Command received a report from the Intelligence Service regarding the advance of the 308th, 312th, and 315th Divisions into Northwest Vietnam. Instead of organizing lightning-fast raids to hold back our main forces, Navarre argued that our main forces were not yet capable of destroying fortified positions like Na San, and that occupying Dien Bien Phu and establishing a strong fortified complex there was entirely correct. If the enemy's main forces dared to advance there, the French expeditionary forces needed to adapt their strategy, transforming Dien Bien Phu into a solid fortress, serving as both a stronghold and "a trap or a crushing machine, ready to crush the enemy's steel divisions, while simultaneously protecting Laos," thus preventing major offensives by the enemy's main forces into this "useful delta."

After inspecting the area (Dien Bien Phu) and thoroughly reviewing intelligence reports on the enemy's main attack routes during the 1953-1954 winter-spring campaign, Navarre decided to accept the challenge of engaging in battle with us at Dien Bien Phu. In a directive (dated December 3, 1953) sent to Conny, Commander of the Northern Front, Navarre tasked the French Expeditionary Force Command in Northern Vietnam with defending Dien Bien Phu at all costs and reinforcing its defenses, building Dien Bien Phu into an "impregnable fortress," a stronger stronghold than Na San. Specifically, it was necessary to parachute in three more mobile combat battalions, increasing the Dien Bien Phu defense force from six battalions to nine infantry battalions and approximately three artillery battalions. As for the units stationed in Lai Chau, they could be maintained if conditions permitted, or withdrawn to reinforce Dien Bien Phu. On December 5, 1953, the paratrooper units that landed at Dien Bien Phu were transformed into the Northwest Operational Group, abbreviated as GONO (Groupement Opérationnel du Nord Ouest). A few days later, Nava's directive to reinforce Dien Bien Phu with three additional battalions was also implemented.

Prior to the day our troops launched the attack on Dien Bien Phu, this fortified complex had been reinforced with 17 infantry battalions, 3 artillery battalions, 1 engineering battalion, 1 tank company, 1 transport company with approximately 200 vehicles, and a standing air squadron of 14 aircraft. The total number of troops was 16,200. With such a strong force, the enemy had deployed a dense defensive system of up to 49 strongholds, organized into 8 clusters, each cluster being a multi-layered firepower system, including: Gabriel (Independence Hill), Beatrice (Him Lam); Anne Mari (strongholds northwest of the airfield such as Ban Keo, Cang Na...); Huyghet (stronghold cluster west of Muong Thanh Airfield, right bank of Nam Rom River); Clodin (stronghold cluster south of Muong Thanh Airfield, right bank of Nam Rom River); Elian (Eastern stronghold, left bank of the Nam Rom River, De Castries' command post area); Dominonich (East airfield stronghold, left bank of the Nam Rom River); Izabel (Hong Cum).

These eight fortified clusters were organized into three major parts: The first part was a central battleground, consisting of five strongholds located right in the middle of Muong Thanh (the district capital of Dien Bien Phu). This was the most important part, directly responsible for protecting Muong Thanh Airfield – the “heart” and “stomach” of the fortified complex. De Castries concentrated two-thirds of his forces here, with eight infantry battalions alone. The second part consisted of two fortified clusters located about 2-3 km north and northeast of the central battleground, tasked with protecting the central battleground from the most dangerous directions and expanding the safe airspace over Muong Thanh Airfield. The third part, located 7 km south, included the Izabel stronghold cluster with a reserve airfield and organized as an artillery base to support the central battleground in defensive operations. In addition, the enemy also organized a strong reserve force consisting of 3 infantry battalions and 1 tank company to perform mobile combat duties, distributed between the central battleground and the southern stronghold (I-da-ben).

GONO's command bunkers were built quite solidly, ensuring they could withstand 120mm mortar rounds. Each stronghold had winding trenches and communication trenches connecting the command bunkers, ammunition bunkers, and sleeping quarters. The sides of the communication trenches had anti-aircraft shields to protect against artillery fire. The gun emplacements were built three meters thick and covered with iron plates. Each stronghold was surrounded by multiple layers of barbed wire fences, 50-75 meters thick. In important directions, the width of the barbed wire fences was 100-200 meters. Interspersed within and between the barbed wire fences were dense minefields... Furthermore, to increase the firepower of the fortified complex, the enemy could mobilize local air forces or those from the lowlands to directly support Dien Bien Phu, or indirectly by bombing supply routes, warehouse systems, and our rear forces. Furthermore, the Dien Bien Phu fortified complex had nearly 50 large artillery pieces, arranged in two bases, Muong Thanh and Hong Cum. These artillery positions could provide fire support to all other strongholds within the Dien Bien Phu complex. In particular, the enemy also equipped their soldiers with new weapons such as flamethrowers, infrared guns for night firing without lights, and anti-smoke devices...

With its powerful forces, modern weapons, and solid fortifications, Dien Bien Phu became "the strongest fortified complex in Indochina." However, in his book "General Navarre and the Battle of Dien Bien Phu," author Jean Pouget acknowledged that: "Of course, no defensive position can have absolute value. No defensive position can hold up if the enemy decides to capture it at all costs. The Maginot Lines of France and the Siegfried Lines of Germany were both breached in World War II; NATO's European Wall and China's Great Wall could also collapse if war broke out."

And in fact, the "giant trap" of Dien Bien Phu has proven to be the "graveyard" of expansionist and authoritarian ideologies, and the place where "colonialism rolled downhill and disintegrated"!

Text and photos: Khoi Nguyen

(This article uses material from the book "Dien Bien Phu: A Milestone in the Era" - Information and Communications Publishing House).

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