It all started in 2001, when a bulldozer driver heard a scraping sound as his machine's blade bit deep into the dirt. Working at a new real estate development site on the west end of Chengdu, capital of Southwest China's Sichuan Province, the driver looked down to see what his scoop had snagged. He had struck a collection of golden and jade objects in the earth.

Soon after construction workers and passers-by rushed to the site, snapping up the treasures and scurrying off. Those too late to get anything were disgruntled, and then reported the incident to the city police.

And so the world learned of the discovery of a mysterious 3,000-year-old Jinsha Kingdom lying on the Chengdu plain.

"The Jinsha culture is quite different from those in other parts of China, and yet is scarcely mentioned by Chinese historians," says Zhu Zhangyi, a veteran archaeologist who is deputy-curator of the Jinsha Museum. "The harsh geography made it difficult for outsiders to enter the kingdom and so it was able to preserve its endemic culture."

Sacrificial rites were very important in the ancient kingdom and involved the use of an astonishing amount of gold ware and elephant tusks.

Over the past six years, the site has yielded up about 6,000 gold, jade, bronze and stone artifacts, tens of thousands of pottery items and also hundreds of elephant tusks.

The Chinese character jinsha literately means gold sand. True to its name, the site has proved extraordinarily rich in gold relics.

Chinese people typically use gold as jewelry - earrings, bracelets or necklaces. "But the Jinsha people used gold for sacrificial purposes. They made gold masks, head ware and various shaped objects in finely worked gold, such as horn-shaped or tape-shaped gold ware," notices Sun Hua, an archaeologist from Peking University.

Experts are flabbergasted by the ancient people's skill in making gold artifacts. Two relics in particular showcase their technical prowess. One is a round gold foil bearing images of the sun and of four flying birds. The foil made of 94 percent pure gold is only about 0.02 centimeters thick, the width of a piece of paper, and 12.5 centimeters in diameter.

Some have speculated that the 12 beams around the sun represent the 12 months, while the four flying birds the four seasons. "No one can say for sure what the images really mean," Zhu says, "but we do know that the ancient kingdom worshipped the sun and birds."

Others have said the Jinsha people may have believed the sun was carried from east to west on the backs of birds. Images of the sun and birds appear on many Jinsha relics. The piece, dubbed the Sun and the Immortal Birds, has since become a logo for Chinese cultural heritage protection.

Another important piece of gold ware is a gold mask, discovered in February 2007. The mask was likely worn by sorcerers who communicated with divine forces.

It is 19.5 centimeters wide, 11 centimeters long, 0.04 centimeters thick and weighs 46 grams.

"Gold masks were not common in China at that time, but widely used in Egypt and the Middle East. Some foreign visitors said the mask reminded them of people in their countries," says Zhao Bisong who works at the museum.

"It's humbling to realize that our ancestors were able to make such vivid and striking things."

"The similarity in facial features provides clues about exchanges between the ancient Shu Kingdom, now Sichuan Province, and regions of western Asia," Zhu says.

Sichuan is known for pandas rather than elephants. Despite this, literally tons of elephant tusks have been extracted from the site. Measuring 1.6 meters long on average, with one gigantic 1.85-meter tusk, the elephant tusks are an impressive sight.

"One thing is for sure, they are from Asian elephants. Experts are analyzing the tusks to figure out how big the elephants were," Zhu says.

Elephant tusks are not easy to preserve. After excavation, there is the risk that exposure to the air could turn them into white powder. "We have preserved some of the elephant tusks in organic silica gel for display purposes but most of them have been reburied where they were found - to protect them," says Zhu. "Preserving elephant tusks is a challenge for scientists in the world."

It is not clear what the elephant tusks were used for. A drawing inscribed on a piece of gold ware shows a man on his knees carrying an elephant tusk on his back.

"The elephant tusks must have been used in religious rituals, but we don't know what kind of god the elephant tusks were offered to or how they were used in the rites," Zhu says.

One of the greatest mysteries of Jinsha culture is that it left no written characters, despite the fact that most ancient cultures were already developing and using characters at that time.

Ancient Chinese used tortoise shells for divination purposes. They would burn the tortoise shells and then predict the future or tell people's fortunes by studying the rifts and patterns on the backs of the shells - called "oracle bones".

Most oracle bones in the vast plain of China carried inscriptions showing the date of the fortune-telling operation, the identities of the people who carried it out or gave some clues as to why divine forces were being consulted. But the oracle bones excavated in Jinsha have no characters on them at all.

"It's very surprising because their culture was quite sophisticated and should have developed characters like other cultures across the world," Zhu says.

"Archaeologists guess they might have written characters on things that did not last, such as leaves or pieces of bark."

(China Daily July 19, 2007)