The Battle of Núi Bop (3–4 January 1885) was a French victory during the Sino-French War. The battle was fought to clear Chinese forces away from the French forward base at Chu, and was an essential preliminary to the Lạng Sơn Campaign in February 1885.
Background
In late September 1884, large detachments of the Guangxi Army advanced from Lạng Sơn and probed into the Luc Nam valley, announcing their presence by ambushing the French river gunboats Hache and Massue (of the Tonkin Flotilla) on 2 October. General Louis Brière de l'Isle, the French commander-in-chief, responded immediately, transporting nearly 3,000 French soldiers to the Luc Nam valley aboard a flotilla of gunboats and attacking the Chinese detachments before they could concentrate. In the Kép campaign (2 to 15 October 1884), three French columns under the overall command of General François de Négrier fell upon the separated detachments of the Guangxi Army and successively defeated them in engagements at Lam (6 October), Kép (8 October) and Chu (10 October).
In the wake of these French victories, the Chinese fell back to Bắc Lệ and Dong Song, and de Négrier established important forward positions at Kép and Chu, which threatened the Guangxi Army's base at Lạng Sơn. Chu was only a few miles southwest of the Guangxi Army's advanced posts at Dong Song, and on 16 December 1884 a strong Chinese raiding detachment ambushed two companies of the Foreign Legion just to the east of Chu, at Ha Ho. The legionnaires fought their way out of the Chinese encirclement, but suffered a number of casualties and had to abandon their dead on the battlefield. De Négrier immediately brought up reinforcements and pursued the Chinese, but the raiders made good their retreat to Dong Song.
Although the Guangxi Army had been forced to retreat in the October battles, its commanders had not given up all hope of breaking into the Delta. Driven partly by sheer hunger and partly by the knowledge that the French would sooner or later move against Lạng Sơn, the Chinese renewed their efforts to gain a foothold in the Luc Nam valley in December. The action at Ha Ho was the first indication that a major move was afoot. A week after this engagement a force of 12,000 Chinese troops from the Guangxi Army occupied the distinctive conical hill of Núi Bop, to the east of Chu, and began to lay out a large fortified camp. The Chinese force was under the command of Wang Debang, one of the Guangxi Army's more competent generals, who had defeated a French column in June 1884 in the Bắc Lệ ambush.
The famished Chinese soldiers plundered all the villages in the area for food, earning the hatred and resentment of the Tonkinese farmers. On 23 December the villagers of Lien Son came to the French headquarters at Chu and alerted Lieutenant-Colonel Donnier to the presence of a large Chinese force around Núi Bop.
The French could not allow a force of 12,000 Chinese to remain at Núi Bop, uncomfortably close to their main base at Chu and threatening the flank of the expeditionary corps when it eventually set off for Lạng Sơn. Brière de l'Isle reinforced the Chu garrison in late December, and in early January 1885 de Négrier was ordered to take the offensive against the Chinese.
De Négrier's column was drawn from both the 1st and 2nd brigades of the Tonkin Expeditionary Corps. It included a marine infantry battalion under the command of chef de bataillon Mahias, de Mibielle's Turco battalion and two companies of Tonkinese riflemen. The column also included the 111th and 143rd line battalions and Jourdy and de Saxcé's batteries.
Battle
3 January
Instead of marching directly east from Chu to attack the Chinese frontally, de Négrier decided to cross to the southern bank of the Luc Nam river and make a wide flank march to come in on the Chinese left. To divert the enemy's attention while his main column marched around the Chinese, chef de bataillon Diguet's Legion battalion in Chu would demonstrate against their front.