The Việt Minh attacked the French defence line along Route 4 and the occupying forces in Cao Bằng, Bắc Kạn and Lạng Sơn to wear them down and cut their supply, and took control of Bắc Kạn.
Battle
Cao–Bắc–Lạng campaign
- 15 March 1949
- Southeast Asia
Battle
The Việt Minh attacked the French defence line along Route 4 and the occupying forces in Cao Bằng, Bắc Kạn and Lạng Sơn to wear them down and cut their supply, and took control of Bắc Kạn.