On March 13, 1954, the first phase of the Dien Bien Phu Campaign began. Implementing the determined battle plan, Vietnamese soldiers attacked Him Lam, a strong resistance centre with three bases located on three adjacent hills on Road No.41, which was guarded by the 3rd Battalion under the 13th Demi-Brigade of the Foreign Legion (3è/ 13DBLE).

The loss of Him Lam shocked the command of the French Far-East Expeditionary Corps in the North. However, the French colonialists could not do anything because the Muong Thanh airport area was tightly controlled by Vietnamese artillery. At 7 o'clock on April 14, 1954, Vietnamese soldiers' anti-aircraft artillery shot down the first plane.

Regiment 165 under Division 312 and Regiment 88 under Division 308 attacked the Doc Lap fortification at 2 AM on March 15, 1954. By 6:30 AM, the Vietnamese troops occupied the battlefield and destroyed the reinforced Bac Phi (North African) Battalion, killing more than 400 enemies and captured nearly 200 others. Lieutenant Colonel Piroth, Artillery Commander of the fortification, committed suicide because he could not destroy the Vietnamese artillery as promised to Navarre.

On the morning of March 16, 1954, after receiving the call to surrender that Vietnamese forces sent to the Commander of Ban Keo base, Captain Clarkambre agreed to let the French go to the designated location receiving wounded soldiers, where a lieutenant and several Thai soldiers arrived with stretchers.

On March 17, 1954, Vietnamese soldiers attacked, surrounded, and forced the enemy in the Ban Keo Fortress cluster to surrender and continuously defeated the enemy’s counterattacks. The task of forcing the enemy in Ban Keo to capitulate was assigned to the 36th Regiment.

To prepare for a new offensive phase, from the high mountainsides, our trenches were simultaneously dug all over the Muong Thanh field.

On March 19, 1954, when the French colonialists' reserves of 105mm artillery ammunition and food in Dien Bien Phu began to run out, De Castries telegraphed René Cogny to say that the loss of Dien Bien Phu was inevitable within a short time and he was considering withdrawing to Laos.

Determining the task of building an offensive battlefield and surrounding the enemy is paramount in preparing for the upcoming second attack. The Campaign Command has assigned specific tasks to the units of Group 308, Group 312, and Group 316.

On March 21, 1954, soldiers of divisions at the Dien Bien Phu battlefield continued to dig trenches to prepare for building attack positions as assigned. Logistics, transportation, and civilian units also kept transporting food and additional weapons to the soldiers in Dien Bien Phu in preparation for the second phase of the campaign.

On March 22, 1954, Vietnamese soldiers continued to dig trenches. The two main lines of trenches advancing from the north embraced the Central subdivision on the east and west sides; at the same time, isolate this subdivision from the enemy's Isabelle base cluster in the south.

On March 23, 1954, our soldiers continued building trench warfare positions. At the same time, the enemy also raced to reinforce their defensive positions by placing more roadblocks, digging more tunnels and trenches, and building some more redoubts to the northeast of their stronghold.

On March 24, 1954, according to plan, the soldiers dug trenches and entered resistance centres — Vietnam’s target in the second attack.

On March 25, 1954, the Party Committee and Command of the Dien Bien Phu Campaign convened a conference to discuss and thoroughly grasp the battle plan for the second attack.

On March 26, 1954, the Conference of the Party Committee and the Dien Bien Phu Campaign Command continued with its second working day.

On March 27, 1954, the General Military Commission determined the operational policy for the second attack after the conclusion of the conference on the Dien Bien Phu Campaign, which assessed the situation of the enemy and the Vietnamese troops.

On March 28, 1954, the General Command issued Order No.83-ML/B1, which determined the second attack to “Concentrate absolute superiority in firepower, destroy all the eastern region of Muong Thanh, creating adequate conditions for our troops to switch to a general attack to destroy all enemy troops in Dien Bien Phu”; assign specific tasks to units: 312th Army to destroy bases 201 (D1), 201A (D2), enemy artillery position at 210, the mobile part of Vietnam's 5th parachute battalion.

To prepare for the second stage of the Dien Bien Phu Campaign, on behalf of the General Military Commission, General Vo Nguyen Giap sent a letter to motivate Party members on the frontline on March 29, 1954.

At 6:00 pm on March 30, 1954, the second attack on the Dien Bien Phu fortress group began. The campaign’s artillery continuously fired at de Castries' command post, high points C1, D1 and E1, artillery positions, and maneuver areas of the enemy in Muong Thanh and Hong Cum.

On March 31, 1954, after the first day of fighting in the second attack, the Campaign Command assessed that Vietnamese soldiers had completed an important part of phase 2's mission, but had not yet captured the enemy's key defensive high-point on Hill A1.

At 5 am on April 1, 1954, two enemy tanks and reinforcements appeared at Hill A1.

On April 2, 1954, Regiment 88 received the mission to attack and destroy enemy’s stronghold 311. Realising that the two Thai puppet companies defending the stronghold were losing morale due to the destruction of stronghold 106, Vietnamese soldiers switched to calling on the enemy to surrender.

At 4:30 a.m. on April 3, 1954, the 102nd Regiment (308th Army) was ordered to hand over the battlefield on the eastern slope of Hill A1 to the 174th Regiment (316th Army), to gather at Muong Phang Forest to strengthen forces.

After unsuccessful sieges at positions Hill A1 and 105, the Campaign Command realised that if we continued attacking, our soldiers would suffer great losses without any tangible results. Therefore, the Command ordered a pause on the attacks. The units would continue holding the hill areas we have captured to create momentum for the next battle.

On the morning of April 5, 1954, the Clédic unit had an additional company under the the 8th Parachute Assault Battalion reinforced at Dien Bien Phu, aiming to completely recapture the 105th fortress (Huguette 6).

On April 6, 1954, the Party Committee and the Campaign Command called up officers serving at units from the regiment level and above to attend a preliminary conference on reviewing the second stage of the Dien Bien Phu Campaign.

On April 7, 1954, the trenches of Vietnamese soldiers' troops gradually inched around the Hong Cum Division. Pierre Langlais ordered his soldiers to fill the Vietnamese soldiers' trenches and levelled 20 meters of trenches.

On April 8, 1954, the Campaign’s Command determined to continue implementing the tasks set for the second stage of the Dien Bien Phu Campaign, which was destroying more enemy forces, occupying more important locations, organising attacks and sieges closer to the enemy; tightening the siege and capturing the airport to completely eliminating the enemy’s supply and reinforcement route.

On April 9, 1954, de Castries mobilised a battalion with tanks and strong firepower to launch a counterattack to retake C1 hill to improve their foothold in the eastern central battlefield, but Vietna's Regiment 98, Army 316 continuously broke up their assaults.

The enemy’s counterattack to retake Hill C1 entered the second day on April 10, 1954. By noon, the enemy had captured part of Hill C1. The reinforcements of the 98th Regiment had to use bayonets for close-quarters combat against the enemy.

The enemy's counterattack to occupy Hill C1 entered the third day. At 2am on April 11, 1954, there were no intact trenches or fortifications left on the high tip of the flagpole at Hill C1 fortress.

On April 12, 1954, Vietnamese soldiers continued to threaten the enemy’s fortifications No. 105 and 106.

On April 13, 1954, France dropped 240 tonnes of goods, including 50 tonnes of food, at Dien Bien Phu.

On the morning of April 14, 1954, the first enemy group patrolling the airport, the Muong Thanh field suddenly noticed that the trenches in the west had cut off communication between Huguette 1 (206th fortress) and Huguette 6 (105th fortress) and the central area. Another trench ran straight into Muong Thanh Airport. At noon, the sixth and eighth parachute units tried to open the way to Huguette 1, but were stopped by newly laid minefields and Vietnamese mortar rounds.

In the Southern Division, at 4:00 p.m. on April 15, 1954, a C.119 plane flew and circled several times and then dropped a series of parachutes, including a red parachute that fell near the Vietnamese battlefield. In the evening, Vietnamese soldiers went out to get their parachutes and saw a box that had been brought back to the 57th Regiment Headquarters.

In line with the fighting method directed by the Command and the campaign leadership, units built offensive and siege battle positions in all directions, edging closer and closer to the enemy, only 10-15 metres away in some places.

Fortresses 105 and 206 had important value to the enemy, so they tried to keep these fortresses to protect Muong Thanh Airport and control a relatively large area to prevent Vietnamese troops from attacking.

The preparations had been completed, and the combat missions of the second phase continued to be carried out. Vietnamese soldiers continued to dig trenches surrounding the enemy’s bunkers, with the trenches in many places only 15 to 30 meters away from the enemy bunkers.

Facing the difficult and drastic situations in Dien Bien Phu , on April 19, 1954, the Politburo issued a Resolution to continue to thoroughly grasp the motto “firm attack, firm advance” to achieve complete victory for the Dien Bien Phu campaign.

On April 20, 1954, regiments conducted political activities with deep self-criticism and criticism, and at the same time promoted activities to snipe and capture parachute supplies from the enemy. Regiments 308 and 312 were determined to dig trenches to separate the enemy airport ahead of schedule.

On April 21, 1954, Vietnamese troops dug traffic trenches close to Base 206 and completed the construction of the offensive battlefield and combat preparations. Regiment 312 and Regiment 308 continued to dig the last metres of trenches, completely cutting off the enemy airfield.

On the night of April 21 and morning of April 22, 1954, the 36th Regiment of the 308th Division opened fire to attack the blockhouse at one end of the bridge. Thanks to the trenches extending near the enemy, our soldiers rapidly captured their frontline battle position.

On the morning of April 23, 1954, the 141st Regiment under the 312th Division brought the 428th Battalion to alternate while the 16th Battalion returned to consolidate in preparation for a new battle.

On the morning of April 24, 1954, French troops mobilised the Second Legion Parachute Battalion and five tanks, equipped with artillery and air force support, to launch a fierce counterattack to knock Vietnamese soldiers out of Base 206 and the airport area.

On April 25, 1954, in a state of panic because of the battle on the fronts, the French army sent bombers to the Noong Nhai concentration camp (Thanh Xuong Commune, Dien Bien District), killing 444 ethnic minorities, mostly women and children, and injuring hundreds of others.

On April 26, 1954, with the help of the US, the French Air Force gathered hundreds of aircraft of all types to increase attacks on Vietnamese battlefields and roads in Dien Bien Phu.

On April 27, 1954, during the Political Conference at the front, the communications force was assigned the task of preparing a loudspeaker system for a new propaganda work towards the enemy.

On April 28, 1954, Muong Thanh Airfield was under our complete control, French forces had no option but to airdrop supplies. During the day, our soldiers continued using small forces to encircle the enemy on the ground while actively shooting aircraft to eliminate the enemy’s reinforcement.

On April 29, 1954, after reviewing preparations for fighting, the 304th, 308th, 312th, 316th, and 351st Armies and the 57th Regiment all reported to the Front Command that they were ready for the third attack.

On April 30, 1954, the Front Command informed units that May 1, 1954, would be the launch date for the third attack.

At 5:00 pm on May 1, 1954, Vietnamese soldiers' artillery bombarded many remaining areas of the enemy's strongholds.

At Isabelle (Hong Cum), Regiment 57 tightened the siege and attacked and destroyed many enemy forces. At dawn on May 2, 1954, the enemy had to withdraw from area C. At 4:00 AM the same day, Regiment 209 (Division 312) captured strongholds 505 and 505A (Dominique 3) on the east bank of Nam Rom River.

On May 3, 1954, the French army reinforced Company 2 of Colonial Parachute Battalion No.1 with 1,100 57mm guns and about 400 heavy machine guns, which were dropped at Dien Bien Phu. In Hai Phong, the aircraft carrier Bois Belleau docked at the port.

After 15 hardworking days and nights, a 49-metre-long tunnel was completed. On the afternoon and night of May 4, 1954, nearly 1,000 kg of explosives, divided into 49 packages designed by Nguyen Diet, were put into the explosion chamber at the end of the tunnel, along with 6 explosive lines connected to the primer, slow-burning wires, and one electric detonation line.

On May 5, 1954, Vietnamese troops consolidated the positions they had captured at Eliane 1 (C1) and Dominique 3 (505, 505A).

On May 6, 1954, while the enemy was urgently preparing for withdrawal, Vietnamese troops continued carrying out their attacks. The 316th Army captured strongpoints C2 (Eliane 4) and A1 (Eliane 2).

At 4 am on May 7, 1954, Regiment 174 completely controlled Hill A1 (Eliane 2). At 9 am the same day, Regiment 98 attacked and completely destroyed C2 Base (Eliane 4), capturing 600 enemies. Regiment 165 completed the mission of destroying Base 506 (Eliane 10), north of Muong Thanh.