Posted on 06 Dec 2016
The Battle of Route Coloniale 4 was a battle of the First Indochina War (1945–1954). It took place along Route Coloniale 4 (RC4, also known as Highway 4), a road which was used to supply the French military base at Cao Bang from Lang Son.
The battle lasted from 30 September to 18 October 1950 and resulted in a devastating French defeat. Several units of the French army were annihilated and essentially ceased to exist as fighting units. All told some 4,800 French were killed or wounded while 2,000 went missing or were captured.
During the French Indochina War, French forces attempted to re-establish colonial control of Vietnam, while nationalist forces led by Ho Chi Minh fought for independence. Initially, the Vietnamese guerrilla forces, the Viet Minh People's Army of Vietnam (VPA) , were unsuccessful in dealing with the better -trained and -equipped French forces.
Vo Nguyen Giap, the military leader of the VPA, launched an offensive against the French in early 1950. On 25 May, 2,500 VPA troops overwhelmed the French fortress at Dong Khé, which lay at the strategic centre of RC4, thus cutting the supply line between the French positions at Cao Bang and Lang Son. French paratroops retook Dong Khé on the evening of 27 May and a company of Legionnaires took charge of the fort.
Meanwhile, the VPA regular army grew in size and experience. By the beginning of September, it comprised roughly 100,000 combatants in 70 battalions, with another 33 battalions of regional forces (40,000 men) as well as some 60,000 local support personnel. Giap then began harassing French positions along RC4 in northern Vietnam with mines and ambushes. The French responded by dismantling their small posts along the road and concentrating area forces in the fortified positions at Dong Khé and Cao Bang.
On 16 September, the VPA attacked Dong Khe. It was then garrisoned by some 300 French troops. On 18 September, the fort was overrun after bitter fighting, and only 12 survivors escaped to the nearby post at That Khé. 140 Legionnaires had been taken prisoner, the remainder being killed or missing in action.
That Khe was quickly reinforced on 17 September, who then waited at That Khe while a force of French colonial troops, assembled at Lang Son. Designated Groupement Bayard the combined force comprised 3,500 men under the command of Colonel Le Page.
Meanwhile, General Marcel Carpentier, the commander in chief of French Indochina, decided to evacuate Cao Bang. The commander of the Cao Bang fort, Colonel Charton, was ordered to destroy his heavy equipment and motor transport and evacuate towards Dong Khé. The plan was that Groupement Bayard would fight its way north from That Khe and retake Dong Khé, holding it long enough to link up with the Cao Bang group. This group comprised 2,600 troops and 500 civilians, the latter mostly pro-French Thai partisans and their families.
On 30 September, Groupement Bayard set out from That Khe. However, Giap had concentrated ten battalions around Dong Khé, reinforced by a complete artillery regiment. The VPA rebuffed the French forces, which were forced to pull back and wait for air support. Le Page renewed the attack on 2 October, pushing west to bypass Dong Khé as VPA numbers were overwhelming.
Meanwhile, Colonel Charton's group left Cao Bang on 1 October and contrary to orders he took with him his heavy equipment. The group's movement down RC4 was slowed by VPA ambushes. After bitter fighting, they finally abandoned their heavy equipment and linked up with Groupement Bayard in the hills around Dong Khé on 5 October.
Forced to leave the road and cut through many miles of the jungle with machetes, they eventually fought their way into a real jam – they were sealed off and trapped in a limestone gorge called Coc Xa, where they were completely annihilated by 7 October. Some 130 of the Legion parachute battalion out of the 500 that had jumped emerged from this breakthrough fight and they had only escaped by clambering down lianas shrouding a 75 ft cliff with their wounded tied on their backs.
In an attempt to support the embattled troops, reinforcements were parachuted into That Khe on 8 October, but over the course of the next week were destroyed as well. Only 23 survivors managed to escape to French lines.
Of the more than 6,000 French soldiers and civilians involved in the operation, only 700 reached French lines. Lang Son, the next French base to the south, was abandoned on 17 October. This was an unprecedented disaster because vast amounts of military supplies, enough to supply more than 10,000 men, were left behind. The magnitude of these stocks was unbelievable. Giap’s divisions found all they needed in the way of food, clothing, and medical supplies for years. Far, far more serious was the question of arms and ammunition. Much of what the VPA fired at the French in the years after came from Lang Son. There were 11,000 tons of ammunition, 4,000 new submachine guns, and hundreds of gallons of gasoline.
Panic spread in French-controlled Hanoi and there was talk of an evacuation. Ultimately, however, General Jean de Lattre de Tassigny replaced Carpentier as commander in chief of French Indochina in late 1950 and restored French morale.
With Highway 4 now in the VPA’s hands, they began to enjoy an uninterrupted supply line from Communist China, and were on a sure path to their eventual decisive victory against the French at the Battle of Dien Bien Phu in 1954.
Source: Wikipedia and others