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Inspired by SavoyTruffle's "More Unstable Southeast Asia" Challenge. The POD takes place within the Tonkin Campaign, the French conquest of northern Indochina that got subsumed into a general Sino-French War.

http://en.wikipedia.org/wiki/Tonkin_Campaign

The Wikipedia article describes the Vietnamese attacks on Hanoi and Nam Dinh as being "half-hearted." Given how precarious the French position seems to be in 1883, I figured more proactive Vietnamese might have a chance at being more successful.

In 1883, Alexandre-Eugène Bouët arrives to take command of French forces assigned to destroy the Black Flag Army in order to avenge prior French defeats. Before he can give OTL's orders to recall the isolated French garrisons at Qui Nhon and Hon Gai, the Vietnamese soldiery of the Nguyen Dynasty overrun them. Bouët gives orders to defend Hanoi, Haiphong and Nam Dinh. The Vietnamese, emboldened by their earlier ATL victories against the French, attack Hanoi and Nam Dinh per OTL. Hanoi falls (ATL) and Haiphong likewise (ATL) but Nam Dinh holds due to reinforcements (OTL).

The French hold their council of war in Nam Dinh and decide per OTL to attack the Ngyuen court at Hue. The Battle of Thuan An proceeds per OTL and the French impose the Treaty of Hue.

Meanwhile, the Battle of Phu Hoai goes like OTL. The Vietnamese, spurred by the earlier victories over isolated French outposts, put forward more effort at the Battle of Palan. The French advance on the pagoda at the base of the dyke takes more casualties than they did OTL and then they run into OTL's defenses. When they attack the center of the Black Flag line, the defenders are better-prepared--the 50 Black Flags who were stabbed on the ground in OTL are up and fighting.

Meanwhile, the Vietnamese don't rout on the left and hold out against the Yellow Flags for awhile. Eventually the French and their local allies force the Black Flags to withdraw, but with far fewer casualties than OTL and a lot more for the French.

The French occupy Ninh Binh and its citadel but in TTL there's a battle here. The French win, with their gunboats playing a major role, but there're more casualties. Meanwhile, Vietnamese insurgents overwhelm the French at Hai Duong--although the arrival of a gunboat drives them off per OTL, many French soldiers are killed (unlike OTL, apparently). The garrison is re-established, but this takes time, troops, and resources.

Despite this, the French begin the Son Tay Campaign per OTL. They attack Son Tay on Dec. 18 (several days later due to butterflies) and suffer OTL's losses.

Then the Black Flag army sorties at night. In OTL, they suffered massive casualties while doing this, which in the opinion of a British observer broke them as a fighting force. In TTL, Liu Yongfu is supported more by the Chinese and definitely more by the Vietnamese. The counterattack is ultimately beaten back, but with much more damage to the French and much less damage to the Black Flag Army and their local allies. Included in the French losses are a fair bit of their artillery.

The French attack Son Tay again the next day. The French admiral Anatole-Amédée-Prosper Courbet gets close to the danger to inspire the troops (this is per OTL, but they need more inspiration this time around).

With more Black Flag soldiers surviving and greater participation by the Chinese and Vietnamese, there's more gunfire and Courbet takes one in the head. Son Tay continues to hold.

Charles-Théodore Millot arrives to take command--OTL he relieved Courbet. However, Son Tay is still there and OTL's Bac Ninh campaign does not take place.

As Millot continues the attack on Son Tay, it becomes clearer and clearer the French will not be able to present a fait accompli to the Chinese. Ultimately Millot takes Son Tay, but the Black Flags withdraw in good order, much stronger than OTL. And unlike OTL, they'll be much more willing to assist the Chinese when Millot launches the Bac Ninh campaign, somewhat later and with fewer troops than OTL.

Here is where the French run into trouble. The Black Flag Army harries the French troops as they advance and the morale of the Chinese army holds up. The French attack on Bac Ninh is a bloody stalemate. Due to foreign diplomatic pressure (the British, at behest of the Chinese) and much worse casualties than OTL, the French negotiate a different version of OTL's Tientsin Accord.

http://en.wikipedia.org/wiki/Tientsin_Accord

The Treaty of Hue is reworked to leave Tonkin as a vassal of the Qing Empire and French forces will be removed from Thuan An. Annam is partitioned, with Quang Nam and points south annexed as a territorial buffer for Cochinchina and the rest remaining under the authority of the Nguyen Dynasty. The Black Flag Army is to withdraw from Vietnam--since the initial war aim of the Tonkin Campaign was to chasten the BFA, face must be saved. They do so and retreat into present-day Laos.

As a result, there is no Sino-French War in TTL. The French control the southern half of Vietnam and retain their protectorate over Cambodia. OTL Laos falls under the control of the Black Flag Army, since the Thai are unable to defend it, and Liu Yongfu establishes himself as the power behind the throne of the elderly King Unkham. OTL's French gunboating of Siam doesn't happen, but the geopolitical need for British assistance against Germany leads to a roughly similar outcome.

Now what? I'm ultimately hoping for a more intense French colonization of South Vietnam to the point SV's culture begins to seriously deviate from the rest of the country. However, the butterflies of no Sino-French War are going to flap pretty hard and could create an entirely different situation in the Far East.
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