With the exception of Laos, the largest opium-producing region in Indochina was the adjacent area of northwestern Tonkin (now part of North Vietnam) known as the Tai country. The ethnic geography is quite similar to that of the Shan States of Burma; the upland valleys are inhabited by wet-rice farmers at altitudes unsuitable for poppy cultivation. But on the cool mountain ridges live Meo tribesmen whose highland slash-and-burn agriculture is ideal for poppy cultivation. Since the Meo of northwestern Tonkin had no large population centers or powerful political leaders like Lo Bliayao and Ly Foung, French efforts to organize local militia or regular civil administration in the 1930s had consistently failed. (92) In contrast, the French found it easy to work with the valley populations, the White Tai and Black Tai.
Consequently, as French administrators mapped their strategy for expanding opium production in northwestern Tonkin in 1940, they decided not to work directly with the Meo as they were doing in Laos. Instead, they allied themselves with powerful Tai feudal leaders who controlled the lowland market centers and most of the region's commerce. To make the Tai leaders more effective opium brokers, the French suspended their forty-year policy of culturally Vietnamizing the Tai by administering the country with Vietnamese bureaucrats.
Although the French had confirmed the authority of Deo Van Tri, White Tai ruler of Lai Chau, when they first pacified the Tai country in the 1890s, they had gradually reduced the authority of his successors until they were little more than minor district chiefs. (93) Potentially powerful leaders like Deo Van Tri's second son, Deo Van Long, had been sent to school in Hanoi and posted to minor positions in the Tonkin Delta. However, in 1940 the French reversed this policy in order to use the Tai leaders as opium brokers. Deo Van Long returned to Lai Chau as a territorial administrator. (94) In exchange for French political support, Deo Van Long and the other Tai leaders negotiated with their Meo mountain neighbors for the purchase of opium and sent the increased harvest to the Opium Monopoly in Saigon for refining and sale. After 1940 these feudal chiefs forced Meo farmers to expand their opium harvest; (95) by the war's end there were 4.5 to 5.0 tons of Meo opium available for shipment to Saigon. (96)
This use of Tai leaders as opium brokers may have been one of the most significant administrative decisions the French made during their entire colonial rule. For, in 1954, the French decided to risk the outcome of the First Indochina War on a single decisive battle in a remote mountain valley of northwestern Tonkin named Dien Bien Pbu. The French commanders, boning to protect their ongoing operations in the Tai country and block a Viet Minh offensive into Laos, felt it would be impossible for the Viet Minh to bring in and set up artillery on the ridges overlooking the new fortress. They planned a trap for the Viet Minh, who would be destroyed in the open valley by French aircraft and artillery fire. But on the commanding mountain ridges lived the Meo who had been cheated and underpaid for their opium for almost fifteen years by Tai feudal leaders, who were closely identified with the French.
Thousands of these Meo served as porters for the Viet Minh and eagerly scouted the ridges they knew so well for ideal gun emplacements. The well-placed Viet Minh artillery batteries crumbled the French fortificafions at Dien Bien Phu and France's colonial empire along with them. France's century of official involvement in the Asian opium trade had come to an end.