In order to restore the morale of the garrison and replace the recently destroyed Legion Battalion, on the afternoon of March 14, 1954, René Cogny recklessly let planes pass through Vietnamese soldiers’ anti-aircraft fire net, dropping the 5th Parachute Battalion (5è BPVN) to reinforce its forces at Dien Bien Phu.
On the night of March 14, 1954, Vietnamese soldiers launched an attack on the resistance centre of Doc Lap Hill, a cluster of bases considered to have the best defence organisation in Dien Bien Phu, led by the 5th Battalion/7th Algerian Rifle Regiment (5/7 RTA) and a company stationed by Thai puppet soldiers. According to the plan, the battle on Doc Lap Hill would begin at 4.45 pm on March 14, 1954.
Right at 4.45 pm, the diversionary force opened fire, burned three canvas tents on A1 hill and charged forward to open the fence. The enemy's 105mm artillery from Hong Cum and 120mm mortars from Muong Thanh fired heavily at the battlefield of Battalion 255. But at Doc Lap Hill, due to the rain, Vietnamese soldiers' 75mm mountain guns and 120mm mortars from Him Lam did not arrive in time before the opening fire, so the attack had not yet begun.
At 6.00 pm, Vietnamese soldiers’ artillery began firing at enemy bases, destroying fortifications and threatening French soldiers' morale. While the artillery was firing, Vietnamese soldiers' infantry continued to prepare carefully, waiting for the 75mm mountain guns and 120mm mortars to arrive for the attack.
On March 14, 1954, the People's Army Newspaper, in issue No.131, published "Letter to officers and soldiers at the Dien Bien Phu front" by President Ho Chi Minh. Uncle Ho's letter had a strong impact, promptly encouraging officers and soldiers to raise their spirits to overcome all difficulties and hardships and move forward to destroy the Dien Bien Phu stronghold, successfully ending the resistance war against the French colonialists.
