By Simon Montlake
in Bat Nha, Vietnam
On a hillside temple in southern Vietnam, one of the country's most renowned Buddhist teachers is giving a talk.
This is Thich Nhat Hanh's second trip to Vietnam in four decades
Around 5,000 people, including hundreds of monks and lay followers from overseas, sit listening in a newly-built meditation hall.
Some have spent the night sleeping on mats, waking in the cold dawn to join the morning rituals.
Thich Nhat Hanh, a Zen master, peace activist and bestselling author, has spent the last four decades living mostly in France.
This is only his second trip back to Vietnam since 1966, when he went to the United States to call for an end to the war in his homeland.
He was then forced to live in exile after both South and North Vietnam refused to allow him to return.
In 1969, he led a Buddhist delegation to the Paris peace talks on Vietnam.
Today, he is back in Vietnam on a 10-week tour that is testing the limits of the Communist-ruled country's freedom of expression and faith.
On Friday he will hold a public requiem in Ho Chi Minh City for the souls of those who died in the Vietnam War, including those who fought for US-backed South Vietnam.
The idea is to heal the wounds and divisions of the past. The three-day chanting ceremony is open to all faiths, and even to non-believers.
"Marxists are invited to recite passages and statements from Marx which reflect his spirituality and his love for humanity," said the organisers in a statement.
Sitting on a dais in front of a wooden altar, Thich Nhat Hanh, 81, speaks in a low, calm voice, using everyday examples for his teachings.
In one corner sit around 80 Western followers who have joined the trip, listening to simultaneous translations in French and English.
Thich Nhat Hanh is attracting many followers
"Today, people's minds are on stocks and news headlines. They no longer have time to take care of themselves or their loved ones. And even though they have lots of money, they aren't happy," he said.
"I've met many millionaires. They're not happy people."
It is a message that resonates with younger members of the audience who were born after the war ended in 1975.
Some have taken time off work to join a five-day retreat at this hillside temple, 140km (80 miles) north of Ho Chi Minh City.
Many are curious about Buddhism and how to apply its creed to modern life, as Vietnam's dynamic economy continues to grow and reshape society. They are richer than their parents, but also more open to ideas.
"I'm a Buddhist, but this is the first time I really practice a lot," said Nguyen Thanh Diep, a hotel management consultant.
"I think that for my generation, this Buddhism is more suitable, because it doesn't only talk about Buddha's powers."
Official figures put the number of Buddhist followers in Vietnam at 10 million in a nation of 84 million.
But that number only refers to registered members of official temples, so nobody knows exactly how many Vietnamese practice Buddhism, which is sometimes combined with ancestor worship and Daoism.
Buddhism appeals to many of Vietnam's youth
Since the 1990s, when the authorities eased restrictions on public worship, there has been a widespread religious revival in Vietnam.
The government only recognises six official religions, though, and insists that churches, mosques and temples are strictly supervised.
Leaders of the outlawed United Buddhist Church of Vietnam have been repeatedly detained and harassed in recent years.
It took several months of negotiations before Thich Nhat Hanh got permission for his current visit, which began on 20 February.
Observers say that the requiem, which will be repeated next month in Hue and Hanoi, is a sign that the government feels confident that their guest will not use his public platform to embarrass his hosts.
"It's time for reconciliation, for the real unification of the country," said Phap An, a monk and senior aide to Thich Nhat Hanh.
During his last visit in 2005, the Zen master held a private meeting with Vietnam's former prime minister.
His books, which were previously banned in Vietnam, are now sold in stores here.
Thich Nhat Hanh is trying to plant the seeds of his brand of faith, known as "socially engaged" Buddhism, among young Vietnamese.
It differs from mainstream Buddhism by putting more emphasis on self-development and group discussions of moral and spiritual dilemmas.
At the hillside retreat, 90 new monks and nuns were ordained, most of them in their 20s. They will live at the monastery, which is affiliated to the official Buddhist Church of Vietnam.
Their age profile is deliberate. Organisers call them part of a new "Peace Corps" for Vietnam who can reinvigorate the Buddhist creed.
Gioi Nghiem, an ordained nun for 10 years who runs a monastery in California, says she is encouraged by the numbers of young followers.
"Young people had the idea that the temples were for old people. So we want to inspire young people to come back to the temple," she said.
But overt displays of religion are still an obstacle to a career in government service in Vietnam.
The Communist Party is officially atheist, and officials are expected to keep their faith private.
One university student who attended the retreat was enthusiastic in describing his appreciation for Nhat Hanh's books.
"Not many people know about Zen. They just go to pagodas for sightseeing," he said.
But he was afraid to tell his parents, who work in Ho Chi Minh City's local government, about his interest in Buddhism.
Nor did he want a foreign journalist to use his name in print.