Lạng Sơn
In the wake of these French victories the Chinese fell back to Bắc Lệ and Dong Song, while de Négrier established important forward positions at Kép and Chu, which threatened the Guangxi Army's base at Lạng Sơn. In January 1885 the French concentrated 7,200 soldiers and 4,500 coolies at Chu, in preparation for a major campaign to take Lạng Sơn. The Kép campaign was an essential preliminary to the February 1885 Lạng Sơn campaign, in which the Tonkin Expeditionary Corps captured Lạng Sơn and drove the Guangxi Army out of Tonkin and back across the Chinese border.