The Battle of Đông Khê was a major battle of the First Indochina War. The battle took place in the town of Đông Khê, in what was then known as the northern Province of Tonkin, ending with a Việt Minh victory.
By September 1950, the French outpost at Đông Khê was held by two companies from the 2nd Battalion/3rd Foreign Legion Infantry Regiment of the French Far East Expeditionary Force (CEFEO). The outpost had been designated as the rendezvous point for the evacuation of the small town of Cao Bằng approximately 15 miles (24 km) away to the north. The evacuation was to take place in early October but was forestalled by the
Việt Minh assault which may have indicated that General Võ Nguyên Giáp appeared to be already aware of it.
On 16 September 1950, Việt Minh forces attacked with mortar bombardments and human waves of up to 2,000 soldiers. After two days of close quarter fighting, only a few legionnaires managed to escape.
On 18 September the 1st Foreign Legion Parachute Battalion (1BEP) was dropped south of Đông Khê but was unable to fight their way to recapture the outpost. A week later a column of 3,500 Moroccans assembled at Lạng Sơn to the south under Colonel Le Page and marched up to meet 1BEP. They joined on 1 October and together they moved up to retake Đông Khê. At Cao Bằng, Colonel Charton was ordered to march a column of 1,500 legionnaires and Moroccans south to Đông Khê, creating a pincer attack from the north and the south. This column was burdened with a number of civilians.
Both columns were attacked by the Việt Minh and eventually left the roads in an attempt to outflank the Việt Minh through the jungle. By the time the two columns met on 7 October they had suffered heavy casualties, were short of food and ammunition and had many wounded. Half of the 3rd Colonial Commando Parachute Battalion (3BCCP) and a company of 1BEP replacements were dropped into Thật Khẽ to hold that post before the arrival of survivors from the Charton and Le Page columns. Only 300 men managed to reach the post, which was then abandoned in haste.
Three weak companies of 3BCCP and 1BEP formed the rearguard of the column and by 14 October almost all of them had been killed. Eventually, only 600 men from the two columns fought their way back to French lines. 4,800 were listed as dead or missing. It was by far France’s worst defeat in the First Indochina War so far.
As a result of the disaster, the French government passed a law that French conscripts were prevented from being sent to areas in which military operations were taking place or to take part in them other than in a time of war. This law would have serious consequences in three years time during the Battle of Điện Biên Phủ.