Military hero Nguyen Quoc Tri (right) and soldiers opened fire to attack Muong Thanh airport. Photo: VNA archive

Prepare the battlefield to capture Muong Thanh airport, completely cut off the enemy's supply and reinforcement lines.

Base 105 (Huyghet 6) was one of the important bases, arranged by the French colonialists in the north of Muong Thanh airport, protecting and controlling a relatively large area, in order to prevent our attacks. After a period of careful preparation in all aspects, the General Military Commission decided to use some regiments of Division 308 and Division 312 to attack Base 105.

Leveraging their experience in encroachment, on the night of April 18, 1954, Regiment 165 destroyed stronghold 105 protecting the north of Muong Thanh airport. Thus, the enemy's last stronghold at the north end of Muong Thanh airport no longer existed.

After losing the 105th stronghold in the North, the French colonialists concentrated their forces to launch many counterattacks to retake the lost stronghold, while organizing many units and war vehicles to reinforce the defense line at the Muong Thanh airport intersection. In order to break the enemy's defense, on April 20, 1954, our units defeated many enemy counterattacks, expanded the battlefield through the barbed wire fence at the last position west of the airport and destroyed a number of bunkers protecting the strongholds.

To carry out the mission of destroying the last position in the West and capturing Muong Thanh airport, completely cutting off enemy supplies and reinforcements, the leaders and commanders of the 308th and 312th Divisions determined to mobilize the participating units to dig trenches to divide the enemy airport and complete the target ahead of schedule.

“Our army urgently built up positions, getting closer and closer to the enemy, in some places only about 10 meters from the stronghold fence. The high points in the East that we captured, especially Hill D1, became strong defensive positions to fight the enemy’s counterattacks and were also our starting points for attacks. Our mortar and artillery fire on these high points always threatened the enemy day and night.”

“The 312th Division built a system of positions that were getting closer and closer to the enemy’s position. The Division’s soldiers day and night held every inch of land on high points E, D, C. The defensive positions were reinforced, with fortifications, traffic trenches, combat trenches, gun emplacements, and reserve positions. Observation post D1 became a strong defensive base of the Division with a firepower position for mountain artillery and mortars with solid fortifications. In some places, we and the enemy were only 10 to 12 meters apart. There were snipers who used three types of guns alone...

From the sniper experience of the 36th Regiment of the 308th Division, the encroachment tactic was developed. One of the typical battles of the encroachment tactic was the attack on base 206 (a base near the airport) by the 36th Regiment on the night of April 22, 1954."

Meanwhile, “the soldiers of the 36th Regiment of the 308th Division also began to encounter a new difficulty. The trenches near the stronghold were less effective, they could not stop flank fire as well as grenades thrown from the fort, and they also revealed the position of the troops. Some soldiers were wounded. The speed of digging trenches slowed down. Several new soldiers, who were guerrillas in the enemy's rear, suggested digging underground to reach the enemy bunkers, both to reduce casualties and to maintain secrecy. At first, the cadres were afraid that this method would prolong the preparation time. But when a team tried digging, they found it was no slower than digging open trenches, because they could dig during the day. The digging method was accepted, although it was difficult, it avoided casualties.”

“When our encirclement was approaching the airport, the Campaign Command predicted that if we attacked any point around the airport, the enemy would counterattack. The Command decided to use very strong firepower to attack the counterattackers. Comrade Vuong Thua Vu was assigned to command the overall firepower to fight the enemy counterattack, and the Deputy Commander was Comrade Dam Quang Trung.

The fire group consisted of five howitzer companies, all mortar firepower of the 308th and 312th Divisions and two infantry regiments. The coordination plan between artillery and infantry was organized in a unified manner. The artillery companies calculated the locations and fired at the enemy's intersections, maneuver routes and assembly positions. Deputy Commander Dam Quang Trung and the artillery battalion commanders went to the top of Hong Lech to direct each target on the field.

In the evening of April 20, 1954, the 803rd artillery company, according to the plan agreed with Hong Son - Commander of Regiment 36, fired 20 rounds at stronghold 206. The Commander of Regiment 36 ordered the unit to shout and charge, but in fact it was a fake charge, and the soldiers continued to dig trenches to gradually encroach on the enemy fence.

Our troops attacked the enemy's key positions on Hill A1, May 6, 1954. Photo: VNA documents

Digging underground tunnels to place explosives on hill A1

After many days of actively digging trenches to prepare for the third attack, "the trenches of the units were so close to the enemy that the officers and soldiers of the base were about to attack, like the terrain of an enemy fortification built on a training ground that had been rehearsed many times.

The most elaborate was the preparation to attack the underground bunker on Hill A1. The cadres gave this location a very appropriate name: The nail of the stronghold. A nail that the enemy was determined to fasten tightly, and that we were determined to remove at all costs. By the time the third attack began, we and the enemy had spent a month fighting for every inch of land on this high point. For the enemy, as long as Hill Al remained, the stronghold would remain. For us, destroying Hill A1 would pave the way to annihilate all remaining enemy troops in the stronghold.”

“After four attacks, they still failed to capture Hill A1. The Campaign Commander, General Vo Nguyen Giap, discussed this peak many times in the General Staff. A local resident who previously participated in building the house on Hill A1 recounted: It was a solid house but nothing special. When it was first built, there was no underground bunker.

Listening to the soldiers describe the bunker, this person thought that the Japanese army during their time in Dien Bien Phu had built this bunker to guard against American bombers, or that the French army had converted the old wine cellar into an underground bunker. Later, it was learned that during the two months of building the fortification, the French army used bricks and stones from the house on the hill to turn the wine cellar into a relatively solid shelter with a lot of soil poured on top...

The Campaign Command directed the Military Intelligence Department to firmly grasp the underground tunnel system at A1. Under the direction of the Military Intelligence Department, comrade Nguyen Ngoc Bao, Deputy Commander of Battalion 122, led a reconnaissance team to infiltrate, investigate, and determine the location of the enemy's underground tunnel entrenched at Hill A1. The reconnaissance team clearly discovered the enemy's underground tunnel; leading to the determination of the Campaign Command: to destroy A1, explosives must be secretly placed in the right underground tunnel, only by destroying the underground tunnel can A1 be destroyed.

The engineers proposed to dig a trench along Route 41, separating A1 from A3, also cutting off the French reinforcement route. The 174th Regiment proposed to dig another tunnel from the battlefield at A1 to the underground bunker, place a large amount of explosives there and then detonate. The unit's engineers calculated that this project would be completed within 14 days and ensured that the digging was done in the right direction.

The unit responsible for digging underground tunnels and using explosives was the M83 Engineer Company of the 151st Engineer Regiment of the 351st Engineer-Artillery Division. A special team of 25 officers and soldiers, directly commanded by comrade Nguyen Phu Xuyen Khung, an engineer officer of the Ministry, carried out the work right under the guns of the French army and within the control of enemy grenades.

On the night of April 20, 1954, the work of digging the underground tunnel began. Everyone had to work in a sitting position like a frog's jaw. To ensure secrecy and safety, the work of camouflaging the tunnel entrance was done very elaborately. Outside the tunnel entrance, there was a roof covered with soil to both protect against grenades and artillery fragments thrown from above and to hide the enemy's eyes. The excavated soil and rocks were all put into parachute bags and taken outside, and after pouring, they were also very carefully camouflaged.

The soil on Hill A1 was extremely hard, so Squad Leader Luu Viet Thoang chose the strongest engineering team to open the tunnel. The entire first night, they were only able to dig 90cm into the mountain wall. The French soldiers kept firing and throwing grenades, injuring three of our soldiers. Squad Leader Luu Viet Thoang himself fainted from the pressure. It took three nights to dig the tunnel door.

When digging 10 meters into the mountain, our forces faced more difficulties: lack of air, lights and torches brought into the tunnel were all turned off, the amount of soil dug out from the mountain was increasing while not being detected by the French army. The defenders at A1 had a plan to fight to prevent the French army from advancing to the tunnel entrance. The deeper they dug, the more difficult the work became because of the lack of light and air, so the troops had to take turns going out to breathe. In the trenches, wherever it was convenient to observe the enemy, we arranged snipers, a team of about four to five people to support the engineers digging the tunnel.

The completed tunnel was 82 meters long and led all the way to the top of Hill A1, where a 1,000kg explosive was placed. Most of the tunnel was very narrow, just enough for one person to crawl through.”

Meanwhile, “General Navarre sent to France a report on the military situation in Indochina. According to Navarre, our general counter-offensive took place 8 months earlier than scheduled. General Navarre proposed to the French government either to cease fire before negotiations, or to negotiate without cease fire, while at the same time actively preparing a new combat corps, with French men, American equipment and money, to conduct a new war with enormous means...”

Coordinate with Dien Bien Phu battlefield:

“In the Northern Delta, our troops ambushed on Highway 5, near Nhu Quynh (Hung Yen), destroyed 1 enemy battalion of GM3, captured 85 rifles; 25 medium and submachine guns; and destroyed 3 enemy tanks.”

According to baotintuc.vn