The Battle of Nà Sản was fought between French Union forces and the Nationalist forces of the Việt Minh at Nà Sản, Sơn La Province, during the First Indochina War for control of the T’ai region (Northwest territory).
In the Fall of 1950, General Marcel Carpentier decided to withdraw all military forces from Hòa Bình, capital of the Muong region. In November 1951, General De Lattre, Carpentier's replacement, launched an offensive operation against the Việt Minh in Hòa Bình to reclaim an area he saw as vital for France's future in Indochina. According to De Lattre, capturing Hòa Bình would cut the enemy's supply line between Thanh Hóa and Việt Bắc. Psychologically, reclaiming the province would gain support from the Mường, who had supported neither side, but were leaning more toward the Franco-Vietnamese side. In November 1951, De Lattre mobilized 10 infantry and eight airborne battalions to mount a decisive operation. Giáp counterattacked with three regular divisions, two independent regiments, and regional support troops. The two sides fought hard for Hòa Bình. At the height of the Battle of Hòa Bình, Giáp had 40 battalions fighting his enemies at different locations throughout the province. In January 1952, French forces were winning when De Lattre had to return to France for cancer treatment and General Salan was appointed to take his place. General Salan, who saw the province as an area that was hard to support and to defend, decided to withdraw his troops (Operation Amarante). On 22 February, French troops successfully withdrew from Hòa Bình and regrouped in Xuan Mai two days later.
Eight months after having successfully defended Hòa Binh, General Giáp attacked Nghĩa Lộ in the T'ai region which he failed to take a year earlier. General Giáp used four regular divisions (308th, 312th, 316th and artillery division 351st) to attack the province's southeast and the regional regiment 148th to guard the northwest side against reinforcements. In 10 days, Việt Minh forces not only took Nghĩa Lộ but also seized part of Sơn La and Lai Châu from French control. To avoid further losses, General Salan launched Operation Lorraine to relieve the Việt Minh pressure in the T'ai region and to serve as a diversion while Na San was being built. The operation, led by General François de Linares, started on 9 November and lasted until 19 November. While the operation was going on, General Salan tasked Colonel Jean Gilles of establishing an entrenched fire support base at Nà Sản to stop Giáp's offensive.
Nà Sản, located on Route Provinciale 41 (RP 41), was a valley of 2 km x 1 km surrounded by 24 hills that could serve as natural defense positions. In early October 1952, there was a single outpost and a short airstrip, both guarded by a company under the command of a non-commissioned officer. General Salan used the Hanoi-based French Air Force Dakotas to transport troops and material there in order to complete a fortified "base aero-terrestre" or air-land base allowing a direct confrontation with the Việt Minh divisions.:327
During the battle, Colonel Gilles used a new tactic, called "the hedgehog" (le hérisson), for the first time in Indochina. The hedgehog defense consisted of an outpost surrounded by several armed positions (point d'appui or P.A.). The objective was to provoke an enemy frontal assault, rather than fighting off hit-and-run attacks or falling into ambushes. Nà Sản's hedgehog consisted of 30 P.A. with a complicated trench system, enforced with barbed wires. Its defense forces consisted of 11 battalions (15,000 men) and 6 artillery batteries.
Lieutenant colonel Ducourneau
General Vo Nguyen Giap, Commander of the Tai region Campaign
Commander : Colonel Vuong Thua Tu
Commander : Colonel Le Trong Tan
Commander : Colonel Le Quang Ba
On 23 November at 20:00 Vietminh forces from the 88/308 twice attacked at P.A. 8 and were twice pushed back by the entrenched Franco-Vietnamese troops.
From 24 to 30 November Vietminh forces made night attacks on different points to test French defense. During the days, defending troops patrolled within their fire-support range for reconnaissance.
At 8:00 PM on 30 November, Vietminh forces from 9 battalions attacked P.A. 22 bis and 24, respectively located east and west of the entrenched headquarters. P.A. 22 bis, defended by a company of the 2nd Thai battalion (BT2) was overrun by the 115th battalion (165/312) after 9 hours of relentless attacks, of the 225 men defending the P.A., only one squad was able to escape back to the airfield. P.A. 24 resisted 3 hours of constant attacks by the 102/308 before surrendering.
Colonel Gilles, who wanted to take back the 2 points so close to Na San's headquarters, launched a counter-attack at dawn on 1 December. After a barrage of artillery fire, two companies of the 2e BEP stormed and took back 22 bis. After 7 hard-fought hours, the 3e BPC took back P.A. 24. At 9:00 PM, General Giap's forces launched their all out offensive at Nà Sản. Wave after wave of soldiers relentlessly assaulted several P.A.s, especially 21 bis and 26; sometimes the attackers outnumbered the defenders fifteen to one. All night, Dakotas dropped flares over the battlefields to give support troops visibility to defend the positions. Defending forces continuously fired their cannons into Vietminh human waves while B-26s, Hellcats and Privateers dropped bombs and napalm onto enemy attack waves and positions. The battles raged on until mid-morning on 2 December when all attacks abruptly stopped, leaving behind an eerie silence.
On 4 December after nearly 2 weeks of trying to overrun Na San, General Giap withdrew his troops leaving behind 1,544 dead and 1,932 wounded prisoners. The defending Franco-Vietnamese forces lost close to 2 battalions.[verification needed]
Despite the victory, France was looking for a political solution to get out of Indochina and Na San was abandoned in August 1953. The tactician Colonel Gilles again outmaneuvered General Giap by evacuating the whole camp without a single loss. In "Ba sinh hương lửa", Doan Quoc Sy quoted a Vietminh officer with the forces surrounding Na San, "The enemy withdrew without our knowledge ... until there was only one battalion left ... the enemy was able to escape and save its entire forces because of our poor military intelligence".
The hedgehog tactics earned the French a victory at Nà Sản. As a result, the hedgehog defense became standard practice, and was applied on a larger scale at Điện Biên Phủ.