Editor's note: A national comprehensive research program, launched in 2002, to trace the origins of Chinese civilization, has led to the excavations and studies of key sites that are about 3,500 to 5,500 years old. It has revealed a host of secrets about ancient China, including how early civilizations were formed and how they merged to create unity in diversity. China Daily speaks to experts working at these sites to decode their recent discoveries.

From 5,300 to 4,300 years ago, people from the late Neolithic period moved to a marshland in Hangzhou, Zhejiang province, and settled there to grow rice. They built a complicated dam system and set up a megacity, featuring a unified belief system that lasted for almost 1,000 years.

The glorious civilization at the Liangzhu site in Hangzhou is considered a key clue to the origins of China's 5,000-year civilization, especially after UNESCO inscribed the Archaeological Ruins of Liangzhu City on its World Heritage List in 2019.

"Liangzhu site is well-preserved," says Liu Bin, a veteran archaeologist who discovered Liangzhu city in 2006. "The archaeological achievements in the past decades are enough to demonstrate a civilization that was as glorious as that in ancient Egypt."

Liu's latest book on excavations at the Liangzhu site was published in July.

In 1986, Liu took part in an excavation that unearthed hundreds of exquisite jade articles at high-level cemeteries near Liangzhu city. It unveiled a mature jadeware production industry in Liangzhu culture and also a stratified society.

Two decades later, the veteran discovered ruins of the city walls, and a well-organized capital city of a regional state in the late Neolithic period was unveiled to the public. Ruins of the complicated water conservancy system were found later from 2009 to 2013. It's the first hydraulic project ever found in China from Neolithic times.

"Liangzhu culture has production chains of jade, pottery and stone, a smart dam system, and a city that was well-built on marshland. It gives the world a good example of civilization along the Yangtze River," Liu says.

Wang Ningyuan, a researcher with the Zhejiang Provincial Institute of Cultural Relics and Archaeology, says that the standards used to define a civilization in China are inspired by the Liangzhu site. In the West, scripts are seen as a key standard of a civilization. However, China regards the appearance of a kingdom as the standard.

Evidence of scripts in Liangzhu culture has not yet been found. But, archaeological projects, beginning in 1936, at the site have proved that a developed kingdom existed. Wang says the unique characteristic that makes Liangzhu culture stand out from others is its sophisticated dam system, the first ever of its kind at the time.

"The dams were designed and finished before the capital city was built, which means the prehistoric people had a detailed city plan to build public utilities," says Wang, who is in charge of the archaeological project focusing on the ancient water conservancy system.

Based on experimental testing of the ruins found at the dams, it is believed that they were built roughly 5,000 to 4,950 years ago. It is thought that the system was designed to transport goods, protect against floods and irrigate rice fields. The city wall was built 200 years later.

"I'm shocked by the sophisticated hydraulic system. People then only used very simple tools. I can't imagine how they made it," says Wang. He started work at the site in 2000 and was the one who first discovered the dam.

Wang and his team have discovered more than 30 dams since, and they're far from finished.

The major function of the dams was to transport goods to the capital city that was inhabited by an estimated 20,000 to 30,000 people. At the time, a city housing 5,000 people was regarded as big.

Wang says they found that heavy logs, more than 10 meters in length, were transported through the dam system to Liangzhu city. There were holes in the logs that indicate they were tied together. Heavy stones were also transported via the system.

"It was a very complicated water conservancy system," adds Wang.

Wang says the people of the time seemed experienced at dam building, which means they had produced this type of system before. However, the discovery remains the first of its kind ever unearthed in China.

"To find a dam is much more difficult than to find other relics such as jadeware and pottery. The dams are made using soil and plants and are hard to recognize just by digging pits," he says.

It's common to not find anything, even after digging for a year. This year, for instance, his team only uncovered a piece of pottery.

Wang says the discovery of the dam system at the Liangzhu site may provide a new prospect for archaeologists in China — they might find similar public utilities at other sites.

Prehistoric people in China mainly cultivated rice fields and such types of hydraulic projects were related closely to agriculture.

"Maybe it can become a special archaeological direction in China," says Wang, explaining that at the time, people in the West mainly grew crops that didn't need water irrigation systems like those required by paddy fields. He adds that dams found in the West at that time were very small in scale and used mostly for flood prevention.

The relic park of Laohuling site opened to the public in July. It is situated northwest of Liangzhu city and displays the dams, some of which reach more than 30 meters high.

Last year, the relic park of Yaoshan site opened, where most of the jade pieces were unearthed from tombs of various social levels, including a tomb that is regarded to be that of a ruler. The skill of jadeware production reached a peak in China and Asia in Liangzhu culture, says Wang. It reflected a highly stratified society.

In 1986, a jade piece weighing 6.5 kilograms, called "King of Cong", was found in the tomb of a ruler. The cong, a cylindrical item, with squared-off outer corners, is an iconic item in Liangzhu culture. The King of Cong, the biggest of its kind, was too big and heavy to wear, thus demonstrating the status of the tomb's occupant.

A large jade ax — a symbol representing military power — was also found in the tomb. Both the jade ax and cong have a special emblem engraved on them: a human-shaped deity riding on an animal, a ubiquitous motif seen on other jade items produced at the Liangzhu site.

"Jade in Liangzhu culture is a medium that unified the whole society. The emblem on it never changed. It had a very stable religious system, lasting for nearly 1,000 years," says Wang.

It also proved that there would have been a ruler that controlled a kingdom where people came from different places. Wang's team found lots of pits that prove there were various jade making workshops in the capital city. Some were made for the lower echelons of society and some for nobles.

Craft workshops flourished at the time, such as those producing items from stone, ceramic and wood.

People living in the city were from different places in China. Some might have come from the central regions and others from the south, according to recent DNA tests on bone fragments found in nearby rivers.

Liangzhu in Chinese means a beautiful isle where lakes and rivers run through the land. Rows of paddy fields were cultivated outside the city. Traces of rice were found in a large store, capable of holding up to 200,000 kg of the crop. It was discovered inside the city.

"It was a very brilliant civilization created by prehistoric people migrating from other places," Wang says.

Yao Huimin's home was in a village about two kilometers away from Liangzhu city. The 36-year-old grew up in the area and witnessed firsthand the unfolding archaeological process of the Neolithic city, which dates back 5,000 years.

A series of tombs were found in her village last year. One — the tomb of a female noble — was discovered next to her house. Yao and other villagers moved out from their houses after the excavation project began.

"I'm breathing the same air and enjoying the same land shared by our ancestors. Life here continues and never stops," says Yao, who works at the Liangzhu site management committee, a government body that is in charge of the management and protection of the Liangzhu site.

Liangzhu city, the relic park of Yaoshan site featuring tombs and a belief system, together with the recently opened relic park of Laohuling site focusing on the dams, offer a comprehensive view of the once glorious civilization to visitors.

According to Yao, the number of visitors to the Liangzhu site reached more than 5 million after 2020, despite the pandemic. It's popular among those who want to discover and learn about the origins of China's civilization.

"The general story of Liangzhu culture is depicted by decades of archaeological work. We will focus on more detailed programs to unveil a vivid civilization," says Wang, the veteran archaeologist who has worked at the site for more than two decades.