Since the sensual Oriental dance arrived in Hanoi two years ago, six dance groups have popped up and more than 1,000 women have joined, among them students, businesswomen and journalists.

"I've lived in many places in Asia - Hong Kong, Shanghai, the Philippines, India - but in Vietnam belly dancing took off faster than anywhere else," said Ara Hwang, the South Korean choreographer who brought the dance to Hanoi. "I came here from Shanghai to teach salsa and I saw that Vietnamese women are attractive and have lots of passion, so I thought, why not belly dancing?" she said, sitting in the cafe of her Apsara dance studio.

Hwang said she was surprised to see how the dance form, born centuries ago in the harems of the Middle East, struck a chord with women in urban Vietnam, a society now undergoing rapid change.

"In Vietnamese culture, traditionally you are not supposed to show your feelings," she said. "But I know Vietnamese women have a very, very strong character, and this has given them a way to express themselves."

"It's boosted my confidence," said Huong Giang, a newspaper journalist who got hooked after taking a course to write a story. "It's kind of erotic and exciting."

Not everyone initially shared the enthusiasm. "At first my boyfriend didn't want me to perform," said Nguyen Kieu Trinh, a marketing student. "But he saw how I felt the change and that I feel happier, and now he supports the dancing."

The mind shift seems to be working. More than 500 people showed up this month for Vietnam's Second Belly Dance Festival, held in the Sum Villa, one of Hanoi's swankiest venues.

Through thick clouds of shisha pipe tobacco smoke, in a room laid out with Oriental carpets, the audience was spellbound by the gyrations of Apsara's Bastet Douat troupe and groups called Sahara, JAWA, and Esmeralda.

For the event to go ahead, the government's usually prudish cultural had to give the green light. "It wasn't clear from the beginning," said Hwang. "But they came to the rehearsal, and in the end they accepted that this is an art."

"Vietnamese people are very open-minded, especially the women," she added. "In two years, so much has changed. I feel like this is a revolution."