Battle of Route Coloniale 4

The Battle of Route Coloniale 4, also called the Autumn-Winter Border Campaign (Chiến Dịch Biên Giới Thu Đông) by the Viet Minh, 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.