The Battle of Cầu Giấy or Paper Bridge, fought on 19 May 1883, was one of the numerous clashes during the Tonkin Campaign (1883–86) between the French and the Black Flags.

French explorers followed the course of the Red River through northern Vietnam to its source in Yunnan, arousing hopes that a profitable overland trade route could be established with China, bypassing the treaty ports of the Chinese coastal provinces.

[5] The Vietnamese government, unable to confront Rivière with its own ramshackle army, enlisted the help of Liu Yongfu, whose well-trained and seasoned Black Flag soldiers were to prove a thorn in the side of the French.

The Black Flags had already inflicted one humiliating defeat on a French force commanded by lieutenant de vaisseau Francis Garnier in 1873.

In the summer of 1882 troops of the Chinese Yunnan and Guangxi armies crossed the border into Tonkin, occupying Lạng Sơn, Bắc Ninh, Hưng Hóa and other towns.

On 27 March 1883, to secure his line of communications from Hanoi to the coast, Rivière captured the citadel of Nam Định with a force of 520 French soldiers under his personal command.

Liu's decision to commit the Black Flag Army against the French was to have profound consequences, setting in train a chain of events that culminated eventually in the Sino-French War (August 1884–April 1885).

So I am first making this proclamation: You French bandits, if you think you are strong enough, send your rabble of soldiers to Phủ Hoài to fight in the open field with my tiger warriors, and then we will see who is the strongest.

All three villages were surrounded by thick bamboo groves and clumps of trees, providing excellent cover for the Black Flags and also allowing Liu Yongfu to manoeuvre his men without being observed by the French.

Berthe de Villers immediately deployed his men into line and pushed forward against the Black Flags, clearing them from the villages of Ha Yen Ke and Thien Thong.

Liu Yongfu brought up his reserves, waited until the enemy line was fully committed, and launched a sudden counterattack against the French right wing.

A Black Flag regiment trotted smartly into position with rifles at the slope, deployed into line, knelt down and fired a series of accurate volleys at close range.

[12] Casualties in the Black Flag Army were around 50 dead and 56 wounded out of around 1,500 men engaged, and included two battalion commanders, Yang Zhu'en (楊著恩) and Wu Fengdian (吳鳳典).

The news of Rivière's defeat and death reached Paris on 26 May, and the French navy minister Admiral Peyron declared 'France will avenge her glorious children!'

The Chamber of Deputies immediately voted a credit of three and a half million francs to finance the despatch of a strong expeditionary corps to Tonkin.

In the 1930s Colonel Alfred Thomazi, the historian of the French conquest of Indochina, did his best to rebut such criticisms:If Rivière had been more prudent and withdrawn his column as soon as he had crossed the bridge, when Berthe de Villers was wounded, our losses would have been smaller and the engagement would have remained indecisive.

To fall back at the first contact would have been to lose face, to encourage the boldness of the Black Flags, and to expose the town to attacks which even a modest success could prevent.

Henri Rivière, a Parisian who considered himself anything but romantic, a writer who was also a man of action, died a hero, like Francis Garnier, for believing that nothing was impossible.