The French hoped that by repeating the strategy on a
much larger scale, they would be able to lure Giap into committing the bulk of his forces
in a massed assault. This would enable superior French Artillery, Armour and
air support to decimate the exposed Viet Minh forces. The experience at Na San
convinced Navarre of the viability of the fortified airhead concept.
Battle of Hòa Bình
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 Nà Sản 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