The Tonkin campaign was an armed conflict fought between June 1883 and April 1886 by the French against, variously, the Vietnamese, Liu Yongfu's Black Flag Army and the Chinese Guangxi and Yunnan armies to occupy Tonkin (northern Vietnam) and entrench a French protectorate there. The campaign, complicated in August 1884 by the outbreak of the Sino-French War and in July 1885 by the Cần Vương nationalist uprising in Annam (central Vietnam), which required the diversion of large numbers of French troops, was conducted by the Tonkin Expeditionary Corps, supported by the gunboats of the Tonkin Flotilla. The campaign officially ended in April 1886, when the expeditionary corps was reduced in size to a division of occupation, but Tonkin was not effectively pacified until 1896.
Hanoi and Nam Định (June–July 1883)
Nine years after Francis Garnier's unsanctioned attempt to conquer Tonkin was cut short by the French government in 1873, French and Vietnamese troops clashed in Tonkin on 25 April 1882, when Commandant Henri Rivière seized the citadel of Hanoi with a small force of marine infantry.
After a lull of several months, the arrival of reinforcements from France in February 1883 allowed Rivière to mount a campaign to capture the citadel of Nam Định (27 March 1883). The Capture of Nam Định was strategically necessary for the French, to secure their communications with the sea.
During Rivière's absence at Nam Định with the bulk of his forces, chef de bataillon Berthe de Villers defeated a Vietnamese attack on the French positions at Hanoi by Prince Hoàng Kế Viêm at the Battle of Gia Cuc (27 and 28 March 1883).
Although these early actions deserve to be considered part of the Tonkin campaign, the campaign is conventionally considered to have begun in June 1883, in the wake of the decision by the French government to despatch reinforcements to Tonkin to avenge Rivière's defeat and death at the hands of Liu Yongfu's Black Flag Army at the Battle of Paper Bridge on 19 May 1883. These reinforcements were organised into a Tonkin Expeditionary Corps, which was placed under the command of général de brigade Alexandre-Eugène Bouët (1833–87), the highest-ranking marine infantry officer available in the French colony of Cochinchina.
The French position in Tonkin on Bouët's arrival in early June 1883 was extremely precarious. The French had only small garrisons in Hanoi, Haiphong and Nam Định, isolated posts at Hon Gai and at Qui Nhơn in Annam, and little immediate prospect of taking the offensive against Liu Yongfu's Black Flags and Prince Hoàng Kế Viêm's Vietnamese. Bouët's first step was to withdraw the isolated French garrisons of Qui Nhơn and Hon Gai. He had also been authorised to abandon Nam Định at need, but he decided to try to defend all three major French posts. During June, the French dug in behind their defences and beat off half-hearted Vietnamese demonstrations against Hanoi and Nam Định.
The early arrival of reinforcements from France and New Caledonia and the recruitment of Cochinchinese and Tonkinese auxiliary formations allowed Bouët to hit back at his tormentors. On 19 July chef de bataillon Pierre de Badens, the French commandant supérieur at Nam Định, attacked and defeated Prince Hoàng Kế Viêm's besieging Vietnamese army, effectively relieving Vietnamese pressure on Nam Định.
Establishment of the French protectorate (August 1883)
The arrival of Admiral Amédée Courbet in Ha Long Bay in July 1883 with substantial naval reinforcements further strengthened the French position in Tonkin. Although the French were now in a position to consider taking the offensive against Liu Yongfu, they realised that military action against the Black Flag Army had to be accompanied by a political settlement with the Vietnamese court at Huế, if necessary by coercion, that recognised a French protectorate in Tonkin.
On 30 July 1883 Admiral Courbet, General Bouët and François-Jules Harmand, the recently appointed French civil commissioner-general for Tonkin, held a council of war at Haiphong. The three men agreed that Bouët should launch an offensive against the Black Flag Army in its positions around Phu Hoai on the Day River as soon as possible. They also noted that the Court of Huế was covertly aiding and abetting Liu Yongfu's Black Flag Army, and that Prince Hoàng was still in arms against the French at Nam Định. They therefore decided, largely on Harmand's urging, to recommend to the French government a strike against the Vietnamese defences of Huế, followed by an ultimatum requiring the Vietnamese to accept a French protectorate over Tonkin or face immediate attack.
The proposal was approved by the navy ministry on 11 August, and on 18 August several warships of Courbet's Tonkin Coasts naval division bombarded the Thuận An forts at the entrance to the Huế River. On 20 August, in the Battle of Thuận An, two companies of French marine infantry and the landing companies of three French warships went ashore and stormed the forts under heavy fire. During the afternoon the gunboats Lynx and Vipère forced a barrage at the entrance to the River of Perfumes, enabling the French to attack Huế directly if they chose.
The Vietnamese asked for an armistice, and on 25 August Harmand dictated the Treaty of Huế to the cowed Vietnamese court. The Vietnamese recognised the legitimacy of the French occupation of Cochinchina, accepted a French protectorate both for Annam and Tonkin and promised to withdraw their troops from Tonkin. Vietnam, its royal house and its court survived, but under French direction. France was granted the privilege of stationing a resident-general at Huế, who would work to the civil commissioner-general in Tonkin and could require a personal audience with the Vietnamese emperor. To ensure there were no second thoughts, a permanent French garrison would occupy the Thuận An forts. Large swathes of territory were also transferred from Annam to Tonkin and the French colony of Cochinchina. The French cancelled the country's debts, but required in return the cession of the southern province of Bình Thuận, which was annexed to Cochinchina. At the same time the northern provinces of Nghệ An, Thanh Hóa and Hà Tĩnh were transferred to Tonkin, where they would come under direct French oversight. In return the French undertook to drive out the Black Flags from Tonkin and to guarantee freedom of commerce on the Red River.
Phủ Hoài, Palan and Hải Dương (August – November 1883)
Meanwhile, as agreed at the Haiphong conference, General Bouët duly took the offensive against Liu Yongfu's Black Flag Army. Bouët twice attacked the Black Flags in their defences along the Day River, in the Battle of Phủ Hoài (15 August 1883) and the Battle of Palan (1 September 1883). These offensives met with only limited success, and in the eyes of the world were tantamount to French defeats.
More encouragingly for the French, a column of marine infantry and Cochinchinese riflemen under the command of Lieutenant-Colonel Brionval stormed the Vietnamese defences of Hải Dương on 13 August. The capture of Haiduong was notable for atrocities committed by both the French and the Vietnamese. The French discovered, hung up by hooks from the city walls, the mutilated bodies of several missing French and Vietnamese soldiers of the expeditionary corps. The dead soldiers had clearly been tortured to death, and the French took their revenge by bayoneting the Vietnamese wounded. The capture of Hải Dương secured the French line of communication by river between Hanoi and Haiphong. The French occupied the citadel of Hải Dương and also established a post a few kilometres to the north of the town, at Elephant Mountain.
In November 1883 the French further strengthened their grip on the Delta by occupying the towns of Ninh Bình, Hưng Yên and Quảng Yên. The allegiance of Ninh Bình was of particular importance to the French, as artillery mounted in its lofty citadel controlled river traffic to the Gulf of Tonkin. Although the Vietnamese governor of Ninh Bình had made no attempt to hinder the passage of the expedition launched by Henri Rivière in March 1883 to capture Nam Định, he was known to be hostile towards the French. Accordingly, Lieutenant-Colonel Pierre de Badens (1847–97) was sent to occupy Ninh Bình with a company of marine infantry, supported by the gunboats Léopard and Pluvier. Cowed by the silent menace of the gunboats, the Vietnamese handed over the citadel of Ninh Bình without resistance, and the French installed a garrison there.
The Treaty of Huế remained a dead letter in Tonkin. Vietnamese mandarins sent to Tonkin to support French administration there were sullen and uncooperative, and Prince Hoang declined to withdraw Vietnamese forces from Tonkin. Meanwhile, the Black Flags, with Prince Hoang's active encouragement, stepped up their attacks on French posts during the autumn of 1883. The small French garrisons in Palan and Batang were harassed, and on 17 November the French post at Hải Dương was attacked and nearly overwhelmed by a force of 2,000 Vietnamese insurgents. Only the timely arrival of the gunboat Lynx enabled the defenders to hold their positions.
Sơn Tây (December 1883)
In December 1883 the French took their revenge. Admiral Amédée Courbet, who had replaced Bouët in command of the Tonkin Expeditionary Corps two months earlier, assembled a column of 9,000 men and marched on Sơn Tây for a showdown with Liu Yongfu's Black Flag Army. The decision was of considerable political significance, as an attack on Sơn Tây would bring the French into direct conflict with Chinese troops for the first time in the campaign. China, the traditional overlord of Vietnam, had for months been covertly supporting the Black Flags, and had stationed Chinese troops in Sơn Tây, Lạng Sơn, Bắc Ninh and other Tonkinese towns to limit French freedom of movement. The French government appreciated that an attack on Sơn Tây would probably result in an undeclared war with China, but calculated that a quick victory in Tonkin would force the Chinese to accept a fait accompli. On 10 December 1883, after the failure of diplomatic efforts to persuade the Chinese to withdraw their troops, the French government authorised Courbet to attack Sơn Tây.
The Sơn Tây campaign was the fiercest campaign the French had yet fought in Tonkin. Although the Chinese and Vietnamese contingents at Sơn Tây played little part in the defence, Liu Yongfu's Black Flags fought ferociously to hold the city. On 14 December the French assaulted the outer defences of Sơn Tây at Phu Sa, but were thrown back with heavy casualties. Hoping to exploit Courbet's defeat, Liu Yongfu attacked the French lines the same night, but the Black Flag attack also failed disastrously. After resting his troops on 15 December, Courbet again assaulted the defences of Sơn Tây on the afternoon of 16 December. This time the attack was thoroughly prepared by artillery, and delivered only after the defenders had been worn down. At 5 p.m. a Foreign Legion battalion and a battalion of marines captured the western gate of Sơn Tây and fought their way into the town. Liu Yongfu's garrison withdrew to the citadel, and evacuated Sơn Tây under cover of darkness several hours later. Courbet had achieved his objective, but at considerable cost. French casualties at Sontay were 83 dead and 320 wounded. The fighting at Sơn Tây also took a terrible toll of the Black Flags, and in the opinion of some observers broke them once and for all as a serious fighting force.
Bắc Ninh and Hưng Hóa (January – July 1884)
On 16 December 1883, the very day on which he captured Sơn Tây, Admiral Courbet was replaced in command of the Tonkin Expeditionary Corps by général de division Charles-Théodore Millot, as a result of the despatch of strong reinforcements to Tonkin in November 1883 and the consequent expansion of the expeditionary corps into a two-brigade army division. Although the capture of Sơn Tây paved the way for the eventual French conquest of Tonkin, the French now had to deal with opposition from China as well as the Black Flag Army. Having exhausted diplomatic efforts to persuade the Chinese to withdraw their armies from Tonkin, the French government sanctioned an attack by Millot on the fortress of Bắc Ninh, occupied since the autumn of 1882 by China's Guangxi Army. In March 1884, in the Bắc Ninh campaign, Millot routed the Guangxi Army and captured Bắc Ninh. Millot put just over 11,000 French, Algerian and Vietnamese soldiers into the field at Bắc Ninh, the largest concentration of French troops ever assembled in the Tonkin campaign.