BEIJING, Sept. 18 (Xinhua) -- High in the Qinghai-Tibet Plateau of northwest China, archaeologists have uncovered a rare inscription dating back more than 2,000 years to the Qin Dynasty.

Carved into a rock face, the characters document an imperial tour led by officials of China's first unified empire, providing insight into the political and cultural life of that era.

The inscription showed how people were already venturing onto the Qinghai-Tibet Plateau as early as the Qin Dynasty (221 B.C.-207 B.C.) and stands as vivid historical evidence of China's diverse yet unified civilization.

ANCIENT WORDS, HIDDEN HEIGHTS

In the summer of 2020, during fieldwork on the shores of Gyaring Lake in Maduo County, northwest China's Qinghai Province, Professor Hou Guangliang of Qinghai Normal University and his team made an astonishing find: an engraved stone hidden amid the rugged plateau landscape.

At an altitude of 4,306 meters, the inscription is carved into the base of a quartz sandstone rock, covering an area of about 0.16 square meters. It features 12 vertical lines made up of 37 characters that read from right to left. Remarkably, several key elements, including the date, are still legible after all these years.

The inscription, absent from written records, recounts how Emperor Qinshihuang -- China's first emperor, known for unifying the country and commissioning the Terracotta Warriors and the early Great Wall -- sent alchemists in search of the legendary "elixir of life."

They made a stop at Gyaring Lake in the source area of the country's Yellow River, explained Tong Tao, a researcher at the Institute of Archaeology of the Chinese Academy of Social Sciences (CASS).

Subsequent research revealed that this stone, which dates back to the Qin Dynasty, is the only known inscription still preserved at its original location and at the highest altitude from the era following Emperor Qinshihuang's unification of China.

The date of the inscription aligns closely with historical accounts of Emperor Qinshihuang's intense quest for immortality in his final years, said Wang Zijin, history professor from China's Northwest University.

LOST STORIES, FRESH INSIGHTS

"The moment we found it, honestly, my mind just went blank," said Hou. "We never imagined that near the source of the Yellow River, we could discover ancient calligraphic characters, and they even begin with the character 'huang' (meaning 'emperor' in Chinese)."

The Yellow River, often hailed as China's "mother river," has long been central to the nation's history and culture. Successive dynasties undertook numerous explorations of its headwaters.

From Princess Wencheng's passing through the source of the Yellow River in the Tang Dynasty (618-907) to the worship at the source of the Yellow River by officials in the Yuan Dynasty (1271-1368) and Qing Dynasty (1644-1911), there are many historical records of explorations of the river's source. Yet evidence from earlier periods remains absent from written accounts.

The discovery of the inscription marks a major breakthrough in Chinese archaeology, stressed Bu Xianqun, a historian with the CASS and expert on the Qin and Han dynasties.

"Carved more than 2,000 years ago, it offers the earliest concrete evidence of the Qin Dynasty's presence deep in the Qinghai-Tibet Plateau, extending our knowledge beyond that of previous texts," Bu noted.

Bu added that the inscription sheds light on how early Chinese rulers explored the Yellow River's source, engaged with plateau cultures, reflecting a profound historical and cultural foundation for the formation of the sense of community for the Chinese nation.

MODERN SCIENCE, PAST TRUTHS

After careful study, Tong Tao of the CASS published an article in June, arguing that the inscription dates back to the Qin Dynasty. His findings sparked widespread attention and months of debate, as some experts expressed divergent opinions on its authenticity, age and other details.

China's National Cultural Heritage Administration then coordinated with experts to conduct field investigations and collect data on the stone and its surrounding environment, as well as organized specialized seminars.

Laboratory analysis confirmed that the inscription is carved on quartz sandstone, a rock highly resistant to abrasion and weathering -- a property experts say is "key to its survival over more than two millennia."

In addition, the stone faces southeast, with a mountain behind it and water in front, providing natural protection from strong winds and intense sunlight, further aiding long-term preservation, according to experts.

During the verification process, Chinese archaeologists employed high-precision information enhancement technology to digitally capture the stone without any physical contact or damage, extracting clear images of its surface, decorative patterns, and inscriptions.

Analysis of minerals and metal elements was also conducted, showing evidence of long-term exposure and effectively ruling out recent carving.

Unlike previous cases, this represents the inaugural instance where scientific techniques were systematically employed in analyzing a single ancient stone carving, said Zhao Chao, a researcher of the Institute of Archaeology of the CASS and a participant of the investigation.

The process has pioneered a new model for stone-inscription authentication in China, according to Zhao. ■