[4][5][6] After the outbreak of hostilities on 19 December 1946, the French Union forces had made significant progress by capturing the cities of Haiphong, Hanoi, Lạng Sơn, Cao Bằng and most of the western and southern regions of Tonkin, which was the stronghold of the Việt Minh movement.

During April 1947 Ho Chi Minh made a last attempt to achieve a ceasefire and to continue the independence negotiations with the French government from 1946.

The French supreme command in Indochina under General Jean-Étienne Valluy realized that the tactic of minor assaults to locate the headquarters of the Việt Minh would not lead to an end of the war.

From their intelligence department, they received some information that the location of the headquarters of the Việt Minh was in the city of Bắc Kạn.

Delayed by bad roads, mines and ambushes, it took the French column until 13 October to reach the vicinity of Bắc Kạn, where the Việt Minh put up a strong resistance.

A four battalion riverine force that was supposed to assault up the Clear and Gam rivers encountered so many delays that they played no useful part in the battle.