SHAANXI, Northwest China — Zhu Shihong has no time to waste as he ducks into the “Pit 2” exhibition hall at the Qin Shihuang Mausoleum Museum. After greeting the security guard, he squeezes straight through a gap in the railings and drops down into the dig site.

A shrill alarm sounds, and the crowds of tourists in the hall all turn to stare at Zhu as he strides across the pit. But the 55-year-old barely seems to notice: After three decades working inside one of China’s most famous archeological sites, he has grown used to being the center of attention.

Zhu has good reason to feel preoccupied. He is currently overseeing a major new excavation of the Terra-cotta Army — a series of digs that many experts predict will transform our understanding of the Qin emperor’s ancient guardians.

For years, the Terra-cotta Army has been associated with the image of row upon row of clay soldiers massed in a giant pit. The army is often referred to as the Terra-cotta Warriors in English for this reason: The infantry are the only part of the army that most people are aware of. But, in reality, the warriors were just one component in a larger — and more complex — military force. 

The Terra-cotta Army site is divided into three main areas. Pit 1 was the first to be excavated, and remains the best-known. It is the army’s main infantry unit, consisting of over 6,000 foot soldiers, or “warriors.”

To the northwest lies Pit 3 — fully excavated in the late 1980s — which served as the army’s command center. It contains the figurines of several senior officers housed inside a small command post, from which they would direct their troops.

Then, in the northeast corner of the complex, there is Pit 2. Unlike the other two areas, this pit is largely unexcavated. But it could be the most intriguing of all. Preliminary surveys indicate it contains what Zhu describes as the army’s “special forces” division: a mixed unit made up of mounted troops, archers, and chariots.

Expectations for the excavation of Pit 2 — which Zhu has been tasked with leading — are high. Researchers say the diversity of figures buried there is unique, and they will be able to analyze any finds using a range of sophisticated technologies that weren’t available to previous generations of archaeologists.

The hope is that the project will provide an unprecedented level of insight into the functioning of the Terra-cotta Army — and the Qin empire that created it.

A decadeslong project

It has taken half a century for excavations at Pit 2 to begin in earnest. Farmers in Xi’an, the capital of northwest China’s Shaanxi province, uncovered the first traces of the Terra-cotta Warriors in the early 1970s. Excavations began almost immediately, and initially proceeded at a frenzied pace.

By 1979, hundreds of clay statues had been unearthed, and the site’s fame had spread across China. Archaeologists agreed that the warriors had once formed part of the giant necropolis constructed by Qin Shihuang — the first emperor to unite ancient China — before his death in 210 B.C. 

But researchers were dismayed by the methods being used in Xi’an. The dig was being conducted like a “potato harvest,” and the hastily reassembled statues looked like “cement men,” they complained. Given the unique value of the site, China’s leaders decided to halt excavations until archaeologists had put together a plan to better preserve the site.

Work recommenced several years later, but ever since the emphasis has been on protecting the relics at all costs. Researchers have often preferred to wait until the technology is developed to properly preserve and analyze each 2,200-year-old figure as it is unearthed. Failing to apply the right techniques can be costly: The paintwork on the statues often begins to fade and crumble within seconds of being removed from the ground.

Formal excavations at Pit 2 started in 1994, just after Zhu — then a fresh-faced graduate from Xi’an’s Northwest University — had joined the archaeology team at the Qin Shihuang Mausoleum Museum. Over the following years, Zhu and his colleagues cleared the topsoil from the pit, conducted preliminary surveys, and excavated a small number of artifacts. This included the famous “green-faced figurine” — a statue whose lifelike features and vivid colors shocked the world. 

After that, however, the team hit pause at Pit 2 once again. The second round of excavations began only in 2015, by which time Zhu had risen to become a veteran archaeologist and the project’s leader. The wait has been worth it, Zhu insists. The team now has access to scientific tools that allow them to collect “broader” and “deeper” information about the dig site than in the 1990s, which can often yield crucial insights.

Whereas excavation work used to focus purely on the relics themselves, today’s researchers also collect information about the surrounding environment, including the soil in which the artifacts were lying. Chemical analysis can help researchers recreate what the original object would have looked like over 2,000 years ago, such as by detecting traces of wood, fabric, or paint that degraded over the centuries.

X-ray scanners also help researchers study relics before they are excavated, while ultraviolet cameras allow them to obtain information about objects that cannot be seen with the naked eye. The team has also used hyperspectral image scanning technology to create a color database for the Terra-cotta Warriors, allowing them to judge definitively what the figures really looked like at the time they were painted.

“Digital recording methods eliminate individual human senses and the ambiguity created by language,” says Zhu. “With this system, disputes such as whether something is a ‘green-faced warrior’ or a ‘cyan-faced warrior’ will no longer arise — at least at a data level.”

The Qin war machine

These techniques are not only allowing researchers to piece together a more accurate picture of the original Terra-cotta Army; they are also providing fascinating new insights into the military tactics employed by the Qin.

The Qin army had a formidable record on the battlefield. During the late 3rd century B.C., it conquered six neighboring states in just a decade, unifying China under one emperor for the first time. The army became legendary for its brave soldiers, cunning generals, and sophisticated weaponry and training.

But research at Xi’an is revealing that the Qin forces were even more advanced than previously assumed. For military historians, the Terra-cotta Army offers a unique window into ancient Chinese warfare.

“For researchers or amateur historians of ancient military affairs, they mostly rely solely on historical materials,” Li Shuo, a historian and author of “300 Years of North-South War,” tells Sixth Tone. “The Terra-cotta Army is an extremely rare exception. Such lifelike sculptures provide an unparalleled insight into ancient Chinese military culture and tactics.”

Some Qin innovations have been known for decades, such as their use of a separate command center. The independent command post — which gave generals a better view of the battlefield — also appears to have reflected the Qin’s macho worldview: The hut housing the generals is shaped like the ancient Chinese character for the male reproductive organ.

Other discoveries have come more recently. As researchers have improved their ability to accurately reassemble the warriors in Pit 1 — and even identify what armor and weaponry they once carried — they have begun to understand that the infantry unit was more varied and organized than it first appeared.

The rectangular formation has three rows of lightly armed troops at the front, while the flanks and rear are guarded by a row of heavily armored warriors. In the center are commanders riding chariots and columns of armed troops.

The Qin even appear to have assigned different hairstyles to each kind of infantry. Archaeologists noted long ago that the warriors in Pit 1 all have one of a few different haircuts, such as a jiezi (a kind of topknot), bianji (a ponytail pinned to the back of the head), or yuanji (a bun fixed to the right side of the head). But later research has revealed that the soldiers’ hairstyles also match the kind of equipment they carried.

Analysis of the warriors’ postures and hand gestures, as well as the weapon fragments found in the pit, shows that the warriors with jieze haircuts used a kind of polearm known as a pi. The yuanji and bianji figures, meanwhile, used halberds and crossbows, respectively. The troops are also arranged in formation according to their haircuts: The jieze warriors are placed on both sides of the vanguard, yuanji troops are clustered in the center of the formation, while bianji infantry are nearer the rear.

“Why use hairstyles to distinguish them? Because on the battlefield, this might have been the most obvious sign that generals could identify at a glance,” Shen Maosheng, the leader of the Pit 1 excavation team, tells Sixth Tone.

The “special forces” unit buried in Pit 2 appears to have been even more complex. Earlier research indicates that the site contains statues of over 900 warriors, 470 horses, and 80 chariots. And they are meticulously organized. The unit is divided into four formations: a square of crossbowmen; a square of cavalry; a group of chariots; and a mixed square formation made up of chariots, infantry, and cavalry.

As the archaeologist Yuan Zhongyi has noted, the formations in Pit 2 appear to reflect a maxim from the ancient Chinese military treatise “Sun Bin’s Art of War,” which advises generals to use “more chariots when it’s easy to advance; more cavalry when in danger; more crossbows when facing difficulties.” The four square formations form a curved layout, and contain formations within formations. The squares can be divided or combined depending on the situation, allowing each one to fight alone or become part of an integrated whole.

However, these findings are only based on initial surveys and trial excavations. Only a full excavation will reveal precisely what the figures buried in Pit 2 look like and how they are arranged.

Into the pit

Completing this work will take decades. Excavations in Xi’an proceed at a glacial pace: Researchers not only need to take precautions to analyze and preserve statues as they are unearthed; each figure also needs to be painstakingly reassembled, as most of them are severely damaged.

Pit 1 suffered a major fire several centuries ago, while Pit 2 also shows signs of burning. It is also punctured by holes and wells dug by generations of local farmers. The result is that the figures are smashed into tiny fragments — and often mixed up together — presenting archaeologists with a daunting restoration job.

“Picture yourself carrying a stack of 100 porcelain plates and then suddenly stumbling and causing all of them to shatter into pieces,” says Shen. “The fragments are scattered everywhere, and you have to restore all of these plates to their original form while figuring out their precise order.”

After 50 years of work in Xi’an, researchers estimate that the excavation of the Terra-cotta Army is only one-sixth complete. In Pit 1, more than three-quarters of the warriors remain underground. And Zhu’s team in Pit 2 has only completed around 100 square meters of excavations since the project began in 2015 — a tiny fraction of the pit’s total area.

This early work, however, has already produced some remarkable discoveries. One surprise was that the “crossbowmen formation” in Pit 2 did not only contain crossbowmen: Zhu’s team also found a number of archers. The formation was divided into two parts: with crouching figures who appear to be firing crossbows, and standing figures firing arrows using a heavier bow.

In the chariot formation, meanwhile, the team found that each chariot was drawn by four horses, with two soldiers standing on each side of the vehicle. In reality, the soldiers would have stood on top of the chariots to ride into battle, but the height restrictions in the underground chamber forced the Qin to place them to the side in the mausoleum, Zhu says.

Perhaps the most intriguing find has been a “general figure” — a statue representing an army commander — positioned at the very front of the unit. General figures are extremely rare: Of the more than 1,000 terra-cotta warriors uncovered to date, only nine are senior officers. And this figure is unique due to its unusual placement at the head of the formation.

The general remains a mystery. Zhu’s excitement is palpable as he stands over the unearthed figure, which is lying in pieces on the ground in Pit 2, wrapped tightly in plastic sheets. 

“Is he the highest commander of this ‘special forces’ unit? Why would he appear at the front? Was this characteristic of the Qin army — generals must lead from the front? Or was this particular general known for his bravery and leadership?” Zhu says.

Answering all these questions will take time. A full restoration of the general figure is likely to require over 10 years, Lan Desheng, a restoration expert at the museum, estimates — longer than the Qin army needed to conquer China. 

The team has considered using computer scanning to speed up the process, but so far they have found using it to be impractical.

“To measure the size of the fragments accurately with a computer, they must be cleaned first,” says Shen. “However, all the fragments are irregular hexahedrons, and each face must be cleaned carefully. You can’t rush through it like washing potatoes ... The workload is immense and unachievable. So, we still rely on experienced technicians to manually piece them together.”

And this only includes the visible fragments. Much of the recent groundbreaking work done in Xi’an involves identifying the weapons, carts, and other items made of perishable materials buried in the pits. Many have decomposed in the soil, leaving behind only faint traces that look like cicada wings. But today’s researchers endeavor to restore every detail of the army, from the warriors’ small leather shields to the cloud patterns painted on their war drums.

Recreating these objects requires massive effort. In 2009, archaeologists in Pit 1 excavated the remains of two carts with the traces of a rectangular object stretched across the top. Initially, the team thought it was a che yin — a kind of seat that would be laid on top of wooden carts — but it appeared to be too thin to bear a person’s weight.

Then, in late 2011, the team found the traces of multiple arrowheads neatly arranged inside the object. They realized the object was likely not a che yin, but a long suo, a container used to carry weapons. The remains of the long suo were sent to China Academy of Social Sciences’ Institute of Archaeology for sampling.

There, researchers gently peeled off the surface lacquer skin, and discovered charcoal blocks held together with a layer of silk thread. This was the first time in over 30 years of excavations that traces of silk thread had been detected at the Terra-cotta Army site. And, given that silk work was generally done by women during that period, it was also a rare example of female labor contributing to the project.

For the team in Xi’an, the discovery of the long suo was a reminder of the benefits of its slow, precise approach. Though many in China are impatient for more discoveries, they see themselves as engaged in a multigenerational project.

“We are not excavating to dig up treasures, nor to showcase the underground cultural relics as soon as possible,” Li Gang, director of the Qin Shihuang Mausoleum Museum, tells Sixth Tone. “Instead, we insist on multi-disciplinary, multi-angle, multi-level, and all-round archaeological work, which deeply analyzes the values, spirit, and scientific thoughts embodied in the Qin Shihuang Mausoleum and the Terra-cotta Warriors themselves.”

Editor: Dominic Morgan.

(Header image: A view of Pit 2 at the Terra-cotta Army site, Xi’an, Shaanxi province, 2018. Yu Xiangquan/IC)