Battle of Route Coloniale 4

Battle of Route Coloniale 4
Part of First Indochina War
Date 30 September-18 October 1950 Location Vietnam Result Việt Minh victory
Belligerents
French Union State of Vietnam	Việt Minh
Commanders and leaders
Marcel Carpentier	Võ Nguyên Giáp Hoàng Văn Thái
Strength
6,000 French and 2,000 Vietnamese regulars	30,000 Việt Minh regulars
Casualties and losses
French: 4,800 killed and wounded 2,000 missing or captured State of Vietnam: 1,000+	Unknown

The Battle of Route Coloniale 4 (called Chiến dịch Biên giới [Border Campaign] in Vietnam) was a battle of the First Indochina War. It took place along Route Coloniale 4 (RC4, also known as Highway 4), a road used to supply the French military base at Cao Bằng. French military traffic along the road had previously been subject to an ongoing series of ambushes during 1947–1949.

The battle lasted from 30 September to 18 October 1950 and resulted in a French defeat. Several units of the French army, including some battalions of the French Foreign Legion, were devastated by the Việt Minh and essentially ceased to exist as fighting units.

RC4 in the First Indochina War

During the French Indochina War (1945–1954), French forces attempted to re-establish colonial control of Vietnam, while communist forces led by Ho Chi Minh fought for independence. Initially, the Vietnamese guerrilla forces, the Việt Minh People's Army of Vietnam (VPA), were unsuccessful in dealing with the better -trained and -equipped French forces. Their situation improved in 1949 after the Chinese Communist army of Mao Zedong defeated the Nationalist army led by Chiang Kai-shek. This gave the VPA forces, now almost completely made up of members of the Vietnam Communist Party, a safe haven for organization and training, as well as an initially sympathetic ally to provide them with arms and logistical support.

Võ Nguyên Giáp, the military leader of the VPA, launched an offensive against the French in early 1950. From February to April, his operation Le Hong Phong I developed through the Red River Valley, largely giving the Việt Minh control of northwestern Tonkin, near the Chinese border. The area became a Việt Minh stronghold, except for the RC4 highway.

On 25 May, 2,500 VPA troops overwhelmed the French fortress at Dong Khé, which lay at the strategic center of RC4, thus cutting the supply line between the French positions at Cao Bằng and Lạng Sơn. 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 Bằng. Giap planned to launch another assault on French positions in operation Le Hong Phong II.

On 16 September, five VPA infantry and one heavy weapons battalions attacked Đông Khê. It was then garrisoned by some 300 French troops comprising the 5th and 6th companies of the 2nd battalion of the 3rd Regiment of the French Foreign Legion (3rd REI). 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 by the Foreign Legion's 1st Parachute Battalion (1st BEP), which parachuted in on 17 September. The 1st BEP waited at That Khe while a force of French colonial troops, the Moroccan 1st and 11th Tabors, assembled at Lạng Sơn. Designated Groupement Bayard the combined force comprised 3,500 men under the command of Colonel Le Page. The task force launched an intelligence raid, capturing prisoners who said a massive Việt Minh offensive was planned.

Meanwhile, General Marcel Carpentier, the commander in chief of French Indochina, decided to evacuate Cao Bằng. The commander of the Cao Bằng 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 Bằng group. This group comprised 2,600 troops and 500 civilians, the latter mostly pro-French Thai partisans and their families.

Battle of RC4

On 30 September, Groupement Bayard set out from That Khe, led by the 1 BEP. However, Giap had concentrated ten battalions around Dong Khé, reinforced by a complete artillery regiment, together with the remaining forces from Le Hong Phong I. The Việt Minh 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 Việt Minh numbers were overwhelming.

Meanwhile, Colonel Charton's group, led by the 3rd Battalion of 3rd REI, left Cao Bằng on 1 October; contrary to orders he took with him his heavy equipment. The group's movement down RC4 was slowed by Việt Minh 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.

The French forces were driven into the Coc Xa gorge, where they were completely annihilated by 7 October. Martin Windrow notes that: Some 130 of the Legion parachute battalion out of the 500 that had jumped emerged from this breakthrough fight; they had only escaped by clambering down lianas shrouding a 75 ft cliff with their wounded tied on their backs.^[1]

In an attempt to support the embattled troops the 1st BEP Replacement Company (120 men) under Lieutenant Loth had been merged with 268 men from 3rd BCCP (Bataillon Colonial de Commandos Parachutistes, Parachute Colonial Commando Battalion) under Captain Cazeaux and they were parachuted into That Khe on 8 October, but over the course of the next week were destroyed as well. Only 23 survivors of the 1st BEP, led by Captain Jeanpierre, managed to escape to French lines: it became the first French parachute battalion lost in combat, followed by the 3rd BCCP, of which only 14 soldiers returned unscathed.

Aftermath

Of the more than 6,000 French soldiers and civilians involved in the operation, only 700 reached French lines. Lạng Sơn, the next French base to the south, was abandoned on 17 October and on 18 October the French command evacuated posts south of Lạng Sơn on RC4. 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.

See also

• History of Vietnam
• Việt Minh
• First Indochina War
• French Foreign Legion

Notes

Windrow, Martin: The Last Valley, 2004