Some of the bones had bullet holes, sometimes more than one, inferring that as the soldiers advanced against the enemy, bullets came mostly from the front.

Taking part in his first field study, Wang Ke, a graduate student at Fudan's Department of Cultural Heritage and Museology, was shocked to discover as he swept the dirt from one of the bodies that its epiphyseal plates (plates of cartilage at the end of growing bones) had not yet fully closed, indicating that they belonged to an adolescent.

"At that age, I was in high school, still childish and sometimes fooling around. But my peers decades ago were fighting on battlefields and risking their lives," Wang says.

In Lyuliang, Wen's team re-created facial appearances for the first time. After scanning the skulls, they added anatomical markers when they returned to the lab.

Based on the cranial CT scan data of thousands of contemporary people of both genders and of different ages they had previously collected and information on the average thickness of muscular and soft tissues, combined with the physical information of the remains, they were able to make 43 successful digital facial re-creations.

"Studying these undocumented soldiers buried in Nancun helps us learn about revolutionary history from a grassroots perspective, how they lived and what they went through.

"They cannot and should not be forgotten. We hope their loved ones are able to find them and they will eventually have names and photos on their gravestones," Wen says.

Through DNA matching, Cui Yuqi was able to find his uncle Cui Haizhi, whose high nose bridge, thin lips and narrow eyes resembled those of his father.