"...porous borders. The northern and western peripheries of the Vietnamese region of Tonkin are mountainous and heavily forested, and for millennia the villages and, in some cases, tribes in those regions have cared not a whit where borders or frontiers were drawn by either the Kings in Annam, the Emperors in China, or by 1917 the colonial offices in European capitals. The Tonkinese were culturally distinct from China but Hanoi was home to among the largest Chinese communities outside of the Middle Kingdom, and unlike the increasingly Catholic Cochinchina, Tonkin's cultural and intellectual communion with China deepened as the power of the Kuomintang spread across Guangdong and Guangshi. Border checks existed mostly on paper, and French zouaves or sepoys stationed throughout Tonkin were notoriously open to bribes. The tinder, in other words, was extremely dry in Vietnam, and ready to be lit.
One thing that separated Vietnamese nationalist organizations from groups similar to the Kuomintang, however, was that they were not doggedly republican in nature and many moderates even envisioned a role for France in Vietnamese affairs not unlike Germany's longstanding close bilateral relationship with Siam (Germany's protectorate over Cambodia, while less harsh than French colonial rule in Indochina, was much more paternalist in nature). Phan Boi Chau was the movement's chief intellectual architect, having formed the revolutionary society Viet Nam Quang Phuc Hoi, which looked to the Katipunan of the Philippines as a direct inspiration, but the two most important figures by 1917 were not democratic republicans like Chau but rather Prince Cuong De, a close relative of the boy emperor Duy Tan, and Tran Cao Van, an influential mandarin who insinuated himself into the imperial inner circle in Hue and quickly established himself as the power behind the throne.
What separated the 1917 uprising from the more successful one a few years later was that France was externally at peace and, after the Ghadar Mutiny had shaken India, was attentively focused on its prize Asian possession. Van's network was riven through with spies who were more than happy to sell out the plotters, and French authorities had diligently reduced the sizes of weapons depots and cycled in well-known loyalists into crucial garrisons around Hanoi and Saigon. While the steady stream of Chinese mercenaries, financed with the opium trade through Haiphong, did not abet, there was some sense that Asia had become a much more dangerous neighborhood and France was more prepared than they may have been a few years earlier.
Nonetheless, the scope and breadth of the May Rebellion (a French name for the revolt) nonetheless caught them off-guard..."
- Our New Asia: Revolution and Retrenchment in the Early 20th Century Far East
"...firewires in the Hai Van Pass and the eruption of artillery bombardments of French positions around Hue signaled that the revolt was on, made official by the royal seal of Duy Tan that endorsed the putsch against the French authorities. Thousands of Vietnamese peasants flocked to the royal banner, ready to fight - already, the rebellion was considerably more legitimate and successful than what the Ghadar faction had pulled off in India two years earlier. Cuong De arrived by boat from Japan, which he admired as an ideological model for the future Vietnamese state, and was declared by his cousin the Emperor as Prime Minister once Duy Tan's evacuation from Hue was secure. Within the span of a few days in early May, not only had Hue fallen, but also strategically important towns on its periphery such as Quang Nam.
The May Rebellion being centered at Hue caused a number of issues right off the bat for the French. It essentially cut Vietnam in half, which theoretically was not a major problem due to French control of the seas thanks to their naval stations at Cam Ranh and Haiphong, but created a strategic opening for the rebels to park themselves astride the major north-south roads. There was also the symbolic factor of Hue, Vietnam's ancient imperial city, being the epicenter of the revolt; this was not some peasant uprising in the rice paddies of the Mekong Delta or the highlands of western Tonkin but the Emperor himself and his fairly sophisticated, French-designed bureaucracy calling for the expulsion of the French government entirely from Vietnamese lands.
As was tradition, the French administration in Vietnam was headed by a civilian, in this case Albert Sarraut, who had returned to the Orient just in January for a second spell as Governor-General. Sarraut was a talented bureaucrat and by the standards of French domestic politics a relative moderate; he admired Southeast Asian "native" art and promoted its enjoyment in the Metropole, but he was also a firm paternalist who viewed the education of the Vietnamese as a method not to improve their standing but rather to Frenchify them culturally and morally. The economy of Vietnam had grown substantially under his previous spell, but he was no military man; to that end, he called upon the Foreign Legion and its notorious Oriental commander, Paul-Frederic Rollet, to be deployed to put down the revolt.
Rollet's station of Saigon meant that he could march rapidly up the coast, which was considered necessary as the rebel forces were moving quickly to secure roads and telegraph cables in the vicinity of Da Nang, only eighty kilometers south along the shore from Hue. The port city fell to Duy Tan's army on May 17th, nine days after the revolt began, and suddenly the rebels could easily accept arms from overseas - with Chinese nationalist cells out of Canton and Hong Kong or Filipino and Japanese sympathizers thought of as the likeliest culprits.
On May 20, Sarraut's residence in Hanoi was attacked by a mob and he was forced to flee to a waiting French cruiser in Haiphong's harbor, and though the French garrison in Hanoi put down the riots and repelled an organized band of revolutionaries headed by Phan Boi Chau and the famed Tonkinese intellectual Nguyen Thuong Hien, it badly destabilized the situation. In the space of two weeks, France had been put badly on her back heels across central and northern Indochina - and it was certain that the world was watching..."
- The French Orient
"...irony of the eruption of the May Rebellion occurring just as the Ghadar Mutiny in India had been mostly put down, though the vast, ungovernable highlands north of Burma and east of India were seen in Paris as being the "Piedmont of Asian revolution" nonetheless, and more than a few at the Deuxieme Bureau were quick to suggest that Cantonese gangs closely affiliated with the Kuomintang had helped finance and arm Duy Tan's rebels.
Despite the ample evidence for the chief ideological support for Duy Tan's revolution stemming from Japanese and Chinese sources (with a dose of inspiration from Ghadarites and the Filipino republicans), Poincaré saw more sinister designs from, where else, Germany. Since 1904, when King Norodom had died, the German protectorate of Cambodia had been ruled by his successor Yukanthor, who took a militantly hard line against the Vietnamese generally and the French more specifically, convinced that French designs on Indochina had never fully ended even after the Bangkok Gunboat Crisis of 1892 and that France would eventually, in what he saw as an inevitable "confrontation" with Germany, seek to indulge Vietnam's historical claims over the Khmer. Siam, an ally of Germany rather than a vassal, had also never forgiven French saber-rattling over the Mekong Valley in 1892 and the forced territorial concessions that Siam had been asked to swallow in the subsequent Treaty of Madrid. Siam's king, Rama VI (personal name Vajiravudh), was perhaps not the titanic, Meiji-esque figure that his father had cut, but since coming to the throne in 1910 nonetheless aimed to continue pursuing his modernizing reforms and had decentralized, democratized and formalized much of the Siamese state without being too reliant on Western methods and theories, building broad popularity with his people even as he declined to promulgate a constitution.
The relationship between Berlin, Phnom Penh and Bangkok was cordial and close, but also complicated; Rama VI was not as instinctively trusting of the "Bavarians" as his father had been, while Yukanthor often chafed at Germany's foreign policy decrees and was horrified at the thought that Berlin might one day do to Cambodia the horrors it had visited upon Mindanao. In short, the idea that the May Rebellion was a plot hatched on the Wilhelmstrasse and carried out by Indochinese interlopers was nonsense. Nonetheless, Poincaré found the idea persuasive, at least in terms of what he coined as "silent support" - money, arms, and a quiet place for Vietnamese rebels such as Phan Boi Chau to hide in exile and map out their next steps, even after Germany denounced the May Rebellion in a diplomatic missive and pledged support for the French response to their "internal matter."
Indeed, the European reaction to Vietnam was one of horror, possibly even more so than what had occurred in Punjab over the previous two years - proportionately and in terms of direct threat to French control, it was the largest colonial revolt since the Spanish-Philippine War. French forces were to be rapidly gathered from across Africa and other parts of Asia and deployed immediately; and more than a few mercenaries from all over Europe and the Americas volunteered..."
- La Politique Mondiale: Poincaré, France and the Waltz of the Great Powers
