BEIJING It has been a very long time since pig's blood figured on the list of common Chinese building materials. Back in the Ching Dynasty, however, it was an essential ingredient in a gruesome shellac used to protect wood from the elements.

So finding an ample supply of this porcine weatherproofing was just one of the many challenges that faced conservationists of the China Heritage Fund in Hong Kong when they set out in 2000 to rebuild the Garden of the Palace of Established Happiness in the Forbidden City here.

After lying in ruins for 82 years, the resurrected garden is nearly complete, part of a broader effort to refurbish the Forbidden City in time for the Olympic games in Beijing in 2008.

But unlike the city's restoration, the China Heritage Fund is rebuilding the garden from scratch, using the specifications that Emperor Qianlong mandated when he had it built in 1740. And it resolved to use not only ancient materials, but also ancient construction techniques. "This was a unique opportunity to revitalize that craft," said Happy Harun, the China Heritage Fund's project director.

Her sentiments are unconventional in Beijing, which is only slowly rediscovering the importance of preserving its architectural heritage. After pulling down its ramparts, gates and imperial arches in the last century in the name of uprooting its bourgeois past, the city's property developers are now bulldozing much of what is left to make way for the nation's capitalist future.

Still, many old temples and buildings remain and the Forbidden City is largely inviolate. But the reconstruction of the Garden of the Palace of Established Happiness has set a precedent for a more meticulous kind of reconstruction that preservationists hope will become more widespread. "The Chinese will have to wake up some day to the fact that things have to be done properly," said Ho Puay-peng, a professor of architectural history at Chinese University of Hong Kong. "They should learn that they have to be done slowly," he said.

Emperor Qianlong cleared space for his beloved garden by knocking down 4,000 square meters, about 43,000 square feet, of buildings that were part of the design originally laid out by the Forbidden City's Ming Dynasty builders three centuries before.

His builders then erected nine pavilions linked by painted walkways that crisscross rockeries and waterways. The central pavilion, where Qianlong could host banquets or meet with officials, was unusual in the Forbidden City in that it was several floors high. The garden was also, Harun says, decorated in a more ornate style than the rest of the palace, reflecting the florid style popular among the Ching emperors. "If Qianlong were alive today," she said, "he'd be wearing Versace."

The garden was also designed to reflect Qianlong's appreciation for literature and the arts. So in addition to relaxation, the pavilions were used to house fine objects, including ceramics, jadeware and jewelry.

It was these treasures, according to a version of history that Bernardo Bertolucci dramatized in his film "The Last Emperor," that the palace eunuchs were accused of stealing by an enraged Emperor Pu Yi. When Pu Yi ordered an inventory, the garden conveniently burned to the ground. A canny merchant is said to have bought the rights to scoop up the remains, from which he extracted a fortune in gold from the sculptures that had melted into the ashes. That was in 1923, a year before Pu Yi was evicted from the Forbidden City and fled to Manchuria.

But there are other versions of the incident. "The story is not very clear," said Ho, the Hong Kong professor. According to another version, Pu Yi was complicit in the pilferage. Another version maintains that Pu Yi was using the garden to screen films and that an electrical short caused by the projector set off the fire.

Whatever the case, the garden was left in ruins, with nothing left to mark its presence except the cracked marble walkways and stone plinths that once supported its graceful pavilions.

In 1999, the China Heritage Fund decided to help resurrect the garden. Run by the Hong Kong businessman (and former Enron director) Ronnie Chan, the fund picked the Garden of the Palace of Established Happiness from a long wish list of restoration projects compiled by the government.

Accurately restoring ancient buildings that had burned to the ground might seem an impossible task, but the fund had lots of help. Researchers found a painting of the garden in a museum in Taiwan and black-and-white photos taken by French Army officers. Better yet, Qianlong had also had the foresight, before handing the throne over to his son in 1796, to have an almost exact duplicate of his favorite garden built on the opposite side of the Forbidden City.

But to make things difficult, the fund resolved to restore the garden to its original state using original materials and techniques. "They did everything according to the book, which can be quite difficult," said Ho, who says he visited the site several times during construction.

Harun and her colleagues pulled more than 80 craftsmen out of retirement to assist the Forbidden City's own workers, including a team of carpenters who could recreate the joinery used in the original construction and a master artisan who could paint by hand the intricate dragons and phoenixes that would be applied by stencil to the cross beams of each walkway. They also enlisted John Sanday, the British conservationist who helped restore Angkor Wat, to determine which of the garden's original plinths and foundation stones could be saved and which had to be replaced.

Workers then had to find the original materials, from the yellowish rocks from outside Shanghai for the garden's rockeries, to the red pine from near Harbin that would be used to make new columns.

And then there was the pig's blood, which along with brick dust and lime was used to coat the columns. Workers needed to apply 10 layers of this malodorous goop with alternating layers of flax to insulate them. Fortunately, plenty of pig's blood was available from a shop specializing in supplies for the constant restoration efforts taking place at Beijing's remaining temples and other old buildings.

When the garden is finally finished, in October, it will serve as a special reception area for guests of the government, off-limits to the seven million tourists who wander through the Forbidden City each year, polishing its bronze statues with their hands and wearing smooth its marble steps.

But the garden's authentic construction will be vulnerable all the same, said Ho, and time will inexorably scrub off its newly minted feel. "It'll look as good as old," he said.