BENEATH the scrubbed-up, ever more modern veneer of Ho Chi Minh City, beats an older, darker pulse; the ancient commerce of opium. Each day, far from the tower blocks, the new wine bars and dance halls, a growing band of addicts slide through the back alleys to hunt for a fix.
They find relief in tiny neighbourhood shooting galleries or the smoking dens of the city's cramped Chinatown - Cholon - now bustling once more.
Ho Chi Minh City, formerly Saigon, may now be the fastest growing city on the planet, but old habits die hard. The addicts are rooted in a tradition that goes back beyond the war with America, beyond French colonialism to trade in British opium from southern China.
Duc's normally addled mind is today very much in the present. He is propped up on a bamboo mat waiting for the pangs of withdrawal to kick in. It is the first day he has been without the poppy for 15 years.
Duc was caught by police emerging from his regular 'cafe' after his morning fix. Before he was formally arrested or charged, he was taken to the Binh Trieu 're-education and rehabilitation centre'.
There he will be detained for six months' job training, medical treatment, counselling, massage and, of course, political education.
'I'm not sure that I want to be here, but my wife will be happy,' Duc says. 'Now is my chance to kick. I feel fine now but I think it is the calm before the storm . . . I am waiting for the pain.