China reaches back in time to challenge the West. Way, way back.

After decades of digging in their own backyard, Chinese archaeologists are now fanning out across the world, trying to unearth connections between Chinese civilization and pivotal moments in global history.

On the plains of southern Uzbekistan, a team of Chinese scientists is working to excavate burial sites they discovered in 2019. The tombs offer potential clues about the fate of a mysterious nomadic tribe with roots in what is now considered China that could rewrite the history of the Silk Road, the network of trade routes that connected the East and West over two millennia.

Chinese researchers have also travelled to Kenya and Saudi Arabia seeking traces of Chinese seafarers from the 15th century. In the South China Sea, others are scouring centuries-old Chinese shipwrecks that could help bolster Beijing’s disputed claims over maritime territory.

The expanding scope of China’s work is challenging long-held beliefs. Some scholars say it has the potential to change the field of archaeology itself, along with China’s place in the sweep of human history.

For years, Xi has pressed China’s scholars, artists and journalists to do a better job telling the country’s story on the global stage. One problem, Xi said in a 2022 speech, is that too few in the West understand the significance and nature of China’s ancient civilization.

“This makes it hard for them to truly grasp China’s past, present and future," he said.

China is participating in more than three dozen overseas archaeological digs, up from barely any before 2010, according to China’s National Cultural Heritage Administration. The same period also saw a more than tripling of articles written by China-based archaeologists in international journals on topics outside China.

One particular focus is the history along the Belt and Road Initiative, the infrastructure project Xi launched in 2013 to revive the influence Chinese empires once wielded through the Silk Road.

The program is part of Beijing’s effort to build up its “geo-cultural power" and assert the reach of Chinese civilization beyond the country’s current borders, said Tim Winter, a senior research fellow at the National University of Singapore who has studied China’s use of heritage to promote the Belt and Road.

Because the evidence it deals with is fragmentary, archaeology offers wide room for interpretation. That ambiguity opens a window for Chinese researchers to push the field in new directions, some archaeologists say.

In search of the Yuezhi

One of their flagship efforts is unfolding in Central Asia, a region where empires clashed and intersected for centuries, and where Western archaeologists have long dominated.

Under clear blue skies in May, Chinese and Uzbek researchers gathered around a 10-foot-deep trench dug into a terrace overlooking the village of Chinor, along Uzbekistan’s Surxondaryo River.

Inside the trench, a young Chinese archaeologist examined soil extracted with a tube-shaped spade as his Uzbek counterpart stood at the edge of the dig, explaining the team’s work to the village mayor. Scattered around them were 24 other dig sites, all ancient graves containing artifacts that challenged long-held assumptions about the region’s history.

The site, called Chinortepa, was discovered by a team under the direction of Wang Jianxin, a 71-year-old archaeologist based at Northwest University in the central Chinese city of Xi’an, the eastern starting point of the Silk Road.

Wang had long argued that the international understanding of the Silk Road—a term popularized in the 19th century by a German explorer—was dominated by Western scholars who naturally tended to focus on exploring how the West had influenced other cultures along the route.

“I want to add China’s voice to the field," Wang said in an interview.

The scholar has spent two decades studying the Yuezhi, a group of nomadic herders who had roamed the grasslands of present-day northwestern China during the first millennium B.C. After a major defeat at the hands of another nomadic tribe in the second century B.C., they fled west, eventually settling in Central Asia—the first people from the East to do so, according to historical records.

Wang long wondered what happened to the Yuezhi after they left China, and he started exploring excavation possibilities in Central Asia as early as 2009. In 2013, three months after Xi announced the Belt and Road Initiative, Wang reached an agreement with Amridin Berdimurodov, then director of the Institute of Archaeology at Uzbekistan’s Academy of Sciences in Samarkand, to launch a joint study of ancient nomadic cultures in Central Asia.

Over the next decade, Wang’s team uncovered dozens of hitherto unknown nomadic settlements in Uzbekistan, stunning other archaeologists active in the region.

Their success stemmed in part from Wang’s years of experience searching for traces of the Yuezhi in China, and his skill in using rock paintings to identify possible excavation sites.

Wang’s expeditions also benefited from an unassuming tool, known as the Luoyang spade, that was first pioneered by graverobbers and is now used by Chinese archaeologists to speed up digs.

Attached to an extendable pole, the spade consists of a foot-long tube-shaped blade, cut in half like a scoop. A trained spade master uses it to pierce the ground, then pulls it back up again with a slight twist to produce soil samples that give archaeologists clues as to what might be below.

“What a strange thing," Komiljon Arziyev, an Uzbek member of the research team, recalled thinking when he first saw it, though he said he was soon won over by its efficiency and even tried to learn how to use it.

In Uzbekistan, the tool allowed Wang’s team to search for graves in flat terrain, such as orchards or farmland, typically ignored by other archaeologists, who tend to spend their time on hillsides looking for the easier-to-spot ruins of ancient cities.

“He looked at things differently and is now helping others see things differently and make new discoveries," said Lothar von Falkenhausen, an archaeologist at the University of California, Los Angeles, describing Wang’s work an “invaluable contribution" to the field.

What the dead reveal

Though Wang himself is immersed in the ancient past, his discoveries in Uzbekistan align well with Beijing’s present-day efforts to portray China as a benevolent player in the region.

The Chinortepa site sits around 30 miles west of a mountain pass through which, roughly 2,000 years ago, the Yuezhi are believed to have arrived on the northern banks of the Oxus River, nowadays known as Amu Darya.

At the time, the land was part of the Greco-Bactrian kingdom, a far-flung eastern outpost of ancient Western civilization known for its Greek-style art and cities. According to the most commonly accepted version, a Yuezhi army of tens of thousands of horse-mounted archers easily defeated the fading kingdom, and eventually established the Kushan Empire, which grew powerful and wealthy by facilitating trade along the Silk Road between the Roman Empire to the west and the Chinese Han Empire to the east.

Wang and his team believe that the idea that the Yuezhi simply overran the land, and subjugated the local population and were the forefathers of the Kushans, is wrong.

The proof, Wang says, is in the ground.

Tombs previously discovered near Kushan fortresses, cities and shrines were often aboveground vaults filled with disorderly piles of bones. Archaeologists say that suggests the Kushans—like the local population before the arrival of the Yuezhi—practiced, as one of their burial forms, defleshing of the dead, whereby bodies of the deceased were left to rot or be devoured by animals before the bones were swept away or stored in mausoleums.

Those tombs are nothing like the Yuezhi graves around Chinortepa, where corpses were buried in underground pits with little chambers to their side.

Wang takes that as evidence that the Yuezhi and the founders of the Kushan Empire weren’t the same people. Rather, he argued, the Kushans were descendants of the local population.

The graves challenge conventional wisdom in other ways. Where the Yuezhi preferred to bury their people at the foot of mountains, the graves near Chinor were on the plain. The offerings discovered inside were also fewer and smaller than those typically found in Yuezhi burial sites.

Based on those differences, Wang’s team concluded that graves belonged to either local farmers who had been influenced by Yuezhi nomads or Yuezhi who had begun to integrate into farmlife.

According to Wang, that suggests the Yuezhi weren’t bloodthirsty colonizers but rather coexisted peacefully with the local population.

Telling the story

The extent to which present-day politics hovers over China’s archaeological ambitions became clear during a Wall Street Journal reporter’s encounter with an Uzbek researcher at the ruins of an ancient Kushan city near Chinor.

“Tell the Chinese that they will not find any traces of the Chinese here," he said.

China’s influence has become a topic of increasing interest among locals in recent years as Beijing has ramped up its investment in Uzbekistan as part of the Belt and Road Initiative. Many Uzbeks welcome it as a force to help their country integrate into the global economy, though there are concerns that China will simply be the newest great power to impose itself on the region.

Asked whether Beijing could use the Yuezhi to make territorial claims, Wang said the notion was absurd because the nomads are a historical people and no one serious would put forth that argument.

Berdimurodov, Wang’s Uzbek partner, said he was grateful to the Chinese archaeologist for shining new light on an understudied topic and was proud of the work.

While his research is academic, Wang says that the results do also “match up with the needs of China and Uzbekistan."

Being able to trace the origins of the Kushan Empire to local people, rather than outsiders, feeds a tale of national resurgence after a period of foreign dominance that lines up favorably with Uzbekistan’s post-Soviet effort to write its own history.

“We are studying the past to understand and shape the present and future," said Wang.

Write to Sha Hua at sha.hua@wsj.com