"Once we excavated a figure with the colors intact," remembers the soft-spoken Liu. "When we took it outside, though, the paint layer started curling up and peeling off right before our eyes. Within ten minutes it was gone. As an archaeologist I felt horrible about it, but there was nothing I could do."

Knowing that some sections of the site might contain more undamaged figures, museum officials slowed the pace of excavation, partly to focus on researching chemical compounds that would stabilize the lacquer layer. In 1988 the Shaanxi Province Cultural Relics Bureau signed an agreement to work with the Bavarian State Conservation Office, based in Munich, Germany. Chemists and art preservationists from both countries tested more than 30 possible compounds before arriving at a solution known as PEG, sometimes used to prevent excavated wood artifacts from drying out too quickly. A version of the compound proved effective on terra-cotta. In 1999 the museum performed its first on-site test, choosing a far corner of Pit 2 that hadn't been damaged by vandals. Working at a painstaking pace with fine tools—"like dentists," says Liu—the team of archaeologists and chemists spent more than a year uncovering six figures.

Suddenly Qin Shi Huang Di's world appeared in Technicolor. The colors—reds and greens and blues and purples—vary from soldier to soldier, and experts have yet to find a connection between color and rank or function. There are unexpected touches like contrasting shirt cuffs. And then there's the strangest discovery of all: one figure whose face is painted green. He may have been intended to frighten the enemy, or possibly the touch was purely artistic.

"You might ask why there aren't other quirks in the soldiers—for example, why do they all pose the same way?" asks Liu, standing in the test excavation site. The pudgy, round-faced archaeologist looks vaguely out of place in the midst of the six fierce warriors, who are kneeling at attention, crossbows at their sides, prepared to rise and fire at the command that still hasn't sounded after 2,200 years. "They can't be disorganized, because they're soldiers," says Liu. "But the colors might have provided some individuality and artistic flair that the form could not. This suggests that when these figures were made, the question of whether they were beautiful or not was even more important than whether they were standard."

But like all the archaeologists I've spoken with, Liu is quick to emphasize that this is only a preliminary theory that must wait until further excavations are done. It's like working on a puzzle where adding new pieces makes the picture larger rather than more complete.

This sense of an expanding mystery is especially vivid at the two experimental pits. In addition to the performers, these digs have yielded a massive 467-pound (210-kilogram) bronze cauldron, the largest ever found at a Qin-period site, and a pit of ceremonial armor made of carved pieces of limestone. The stone-armor pit is strewn with thousands of limestone plates that are charred by a fire nobody can explain. Tests show that the pit containing the cauldron and the entertainers covers about 960 square yards (800 square meters), but officials granted permission for less than 9 percent of it to be opened by the 1999 test excavation. A full-scale excavation will wait until authorities feel that the time is right.