Drug traffickers opened up ancient trade route
Vice, even the most thin-lipped economist will tell you, is often the first branch of commerce to register change.
And so it is at Dien Bien Phu in Lai Chau province, one of Vietnam's most isolated corners.
In a vast hidden valley in the northeastern mountains, it has taken a major heroin trafficking scandal to expose the return of ancient trading links long stunted by the restrictions and austerity of Marxism.
More than 300 kilograms of Golden Triangle heroin was smuggled overland by Laotian, Chinese and Vietnamese traffickers through Dien Bien Phu to Hanoi and beyond.
The syndicate collapsed in a Hanoi court earlier this year when eight people - including senior police - were sentenced to death.
Until then, the valley had been submerged beneath the weight of the historic victory of Ho Chi Minh's Viet Minh rebels over French colonial forces in 1954, forcing Paris to abandon its entire Indochine venture.
Decaying bunkers and rusting bombed-out tanks remain but, other than tourists, few people pay them much mind as they eke out a living in one of Vietnam's poorest regions.
Locals' eyes are now instead fixed on the blue-green peaks that lead towards Laos and China and a new era of prosperity and openness.
If Hanoi and Ho Chi Minh City are now enjoying the fruits of the return to the regional and international community, then Lai Chau hopes it, too, can in its own quiet way. In its sights are Phonsali and Luang Prabang in Laos, and Yunnan province in China.
Local officials say the borders to both countries are now more open than at any other time in recent history.
In a landmark development, residents either side of the Laos-Vietnam border need only a local permit rather than a passport or visa to legally cross for trade.
To the north, crossings into China are also easier than before, if still unofficial. A Chinese-built road linking the three countries during the Cold War is being repaired.
At the centre of the awakened historical links sit the various Thai and Hmong ethnic minorities.
Rice farmers, the Thais dominate the valleys of Lai Chau and form part of a band of common language and culture that stretches from Thailand over the mountains to Yunnan.
Despite the omnipotent Vietnamese administration, they cling to traditional dress, homes of wood and bamboo and still hunt for wild game in what remains of the jungles.
As the money, legal and otherwise, starts to come to Dien Bien Phu, providing electricity and new influences, these cultures face unprecedented pressures after a century of turbulence.