Vietnam Vignette: French Defeats Along RC 4 – Indochina, Fall 1950

The catastrophic defeat suffered by French forces along RC 4 between 30 September and 8 October 1950:
By early in 1950 General Vo Nguyen Giap had built up his forces in the Bac Viet to five divisions. By later that year, after the monsoon season had passed, his newly strengthened Vietminh Army was poised and ready to attack and defeat the French along a rural stretch of road dotted by forts running between Lang Son, Dong Khe, and Cao Bang. The General’s objective was to clear French forces from the area north of Hanoi near the border with China.

In 1949 the Chinese border became a sanctuary for Vietminh operations. With the rise to power of the Communists over Chiang Kai-shek, Ho Chi Minh and Vo Nguyen Giap suddenly had training camps and safe harbor across the border in China. In addition to the strategic depth provided by the Chinese, Chairman Mao tossed in tactical and material support and sent seasoned officers as military mentors and trainers. By fall, Giap saw that he had an opportunity for a quick decisive win against the complacent French defenders– his target was a string of isolated French outposts along Route Colonial 4. The French had taken the road in Operation LEA back in 1947. The captured territory had been held ever since by troops stationed in a series of garrisons erected at intervals along the road.

General Giap felt he had much to gain by attacking those particular garrisons; first, he could ease the process of getting supplies and men from China to his headquarters in the Bac Viet and to his armies in the field; second, he was looking to get his troops some hands-on combat experience; third, he knew that a decisive victory would lead to sky-rocketing morale among the troops; and last he wanted his officers to get experience in deploying conventional units in battle.

By the onset of monsoon season in 1950 (roughly late April) the French had ceased supplying their fort at Cao Bang by truck (air drops only). They had also evacuated several of their other RC4 outposts leaving only the Dong Khe and Cao Bang positions inland from Lang Son (where RD1 linked up from Hanoi). Giap’s first target was Dong Khe, the middle of the three posts, where Moroccan troops manning the garrison were attacked from the jagged Karst Mountains above  by Vietminh forces using American-made 75 mm pack howitzers.  The Moroccans were beaten soundly, relatively few escaped. The French counterattacked quickly by dropping a parachute battalion right into the reeling position. Then the paras pounded the Vietminh, driving them back into the jungle. It proved to be a temporary respite.

At that crucial moment, the French commander Carpentier wavered, he lost valuable time before finally deciding to evacuate Dong Khe and Cao Bang. He may have been working with a lack of intelligence about the size and capabilities of Giap’s forces but more likely he just didn’t respect them, an error that westerners would make repeatedly over the coming years. He was likely also over-confident in his assessment of his troops fighting spirit. He was desperate by that point and needed the French troops to get him out of this tight jam. He also had to devise a way fast to cover the withdrawal from Cao Bang and Dong Khe down RC4.

Carpentier had options: first, was air evacuation, second was a breakout, but Carpentier decided instead for a linkup along RC 4 between the beleaguered squads from the forts to the north and a force he would send up the road to meet them. Presumably then they would fight their way back to the French held Red River Delta together. It was a plan that would require considerable speed and stealth to have a chance. Operation BAYARD was born.

While all of this planning was going on Dong Khe was being attacked a second time and this time the paras were overrun (only a handful made it out alive). Now the Vietminh would concentrate exclusively on smashing the BAYARD expedition and the Cao Bang retreat.

Commanding the fleeing Cao Bang group south was Colonel Charton. Leading the BAYARD expedition north was Lieutenant Colonel Marcel Lepage. BAYARD was a disaster in logistics and execution from the get-go. To start, Carpentier, for some reason, didn’t tell his BAYARD commander Lepage any specifics about his mission!  Finally, belatedly, Carpentier ordered BAYARD to move-out up RC 4 to link up with Charton. The element of speed and surprise had been lost and had actually now turned into a liability because, little did Carpentier and Lepage suspect, they would be up against two Vietminh regiments with more on the way from the Chinese bases, they couldn’t outnumber or outrun them.

It didn’t take long for the BAYARD forces to be stopped dead in their tracks. Soon after, ambushed and harassed, Charton’s men were forced to leave the road and cut through many miles of the jungle with machetes. Lepage and his charges eventually fought their way into a real jam– they were sealed off and trapped in a limestone gorge called Cocxa, there they were annihilated.

The French had also dropped a parachute team behind in the rear to keep the road to Lang Son open and reinforce the vital French fort there. They were ambushed and largely destroyed– only five made it through to the fort according to French Journalist Lucien Bodard. Their respite was short-lived. According to Bodard: “Abandoning Lang Son would mean losing face; it would be a catastrophe from every point of view– military, strategic, political and psychological.” But that is precisely what happened– the evacuation order went out.

Was the evacuation called-for in the face of overwhelming odds or was it a premature surrender? The matter has been hotly contested ever since.  Bodard continues: “everybody knew that the evacuation of Lang Son, as it had been carried out, was henceforward the French Army’s shame… But the most depressing news was that it had been abandoned virtually intact with all its immense stores. 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 Viets fired at the French in the years after came from Lang Son: there were 11,00 tons of ammunition, including some 10,000 75-mm shells (and the Viets had 75-mm guns); there were 4000 new submachine guns; hundreds of gallons of gasoline– an incalculable treasure of military stores.”

Finally came the evacuation of Laokay. If Lang son was considered the front door to China then Laokay represented the back door of Tonkin facing toward Yunnan. With the capture of Laokay all invasion routes were in the hands of the Vietminh. Now they could carry on two wars simultaneously, in the jungles or on the plains. They might attack the Red River Delta and Hanoi or stream into Laos, or both. Now the Viets could take aim at the Thai countries and their feudal chiefs who were allied to the French. This would all be too much for the French to contend with as the war progressed.

It’s interesting to consider that at this same time, sixteen hundred miles to the north, the US Marines had taken Inchon and were fighting for Seoul in S. Korea and the 8th Army was slugging its way north toward Pyongyang and a showdown with the Chinese armies at the Yalu River. This was an important fall season as far as Cold War history is concerened.

Through it all, somehow, the Cao Bang squad under Charton was able to repel repeated Viet Minh attacks and miraculously many made it out alive. The rest of the French Expeditionary Force on the other hand was either on the run or wiped out altogether; eight battalions were destroyed, half of them elite Foreign Legion and parachute troops. French Expeditionary forces lost some 7,000 men and over 3,000 tons of weapons. And even though the human and material losses were demoralizing, it may have been the psychological defeat that resonated even further.

Noted Historian Bernard Fall called it the worst French colonial defeat since the failure of Montcalm nearly two hundred years earlier on the Plains of Abraham at the Battle of Quebec (1759). In the shadow of Giap’s stunning victories along Route Colonial 4 in 1950 the French were in disarray and fearing for their safety and colony. They were making plans to evacuate as many colonists as possible from North Vietnam. Panic was in the air. They responded by sending in a new commander-in-chief, a general of higher caliber than the hapless Carpentier, his name was General Jean de Lattre de Tassigny. De Lattre then built a series of pill-box strongholds around the Red River Delta for defensive and morale purposes (the de Lattre Line). The French dug in.

In the wake of his triumphs General Giap was overly confident, too confident as it turned out, in his army’s ability to capitalize on it’s momentum. The General readied his forces and strategy for an upgrade to phase three conventional warfare. He mistakenly thought the French were ready to fall. He was wrong. He launched a series of over-optimistic attacks on the French perimeter around the Red River Delta which he called his General Counter Offensive in spring 1951. These attacks were expensive failures for the Vietnamese. Large Vietminh infantry units and onrushing human waves were caught in the open and mowed down by French napalm. As a result, Giap failed to take the Delta and his army suffered heavy losses. But to his everlasting credit he learned and adapted, adopting less ambitious tactics in the following years. From then on he adhered strictly to Mao’s military concept of fighting a war of time, distance and will. It would serve him well for decades to come.