The recent public showing of a previously un-exhibited Peking Man fossil has served to remind the world of a long-running mystery. The location was the Zhoukoudian Peking Man Site Museum, 48 km southwest of Beijing. The fossil was a frontal skull fragment discovered 37 years ago. This exhibit was on show from Sept 21 to Oct 7 this year but it reawakens a mystery that has fired the imagination of the world of archaeology for more than 60 years.

The frontal bone on show was discovered in 1966 by the late renowned Chinese paleoanthropologist Pei Wenzhong (1904-1982). It was Pei who discovered the first Peking Man skull. His find at Zhoukoudian in 1929 attracted worldwide attention. Thereafter, German paleoanthropologist Franz Weidenreich and Canadian anatomist Davidson Black together with Pei led several excavations at the site unearthing many Peking Man fossils including five complete skulls.

The archaeological work at Zhoukoudian was interrupted by the Japanese occupation of Beijing in 1937. In November 1941 Chinese scientists tried to get the Peking Man fossils to safety in the United States in the safe keeping of US Marines who were about to evacuate the country. Unfortunately, the plan to spirit the skulls out of the country was not to succeed for Japan bombed Pearl Harbor on Dec. 7, 1941 and all the US troops in China became prisoners of war. All five skulls mysteriously disappeared, and there has been no trace of them ever since.

After the founding of the People's Republic of China, excavation work was resumed at the Zhoukoudian site. Human fossils belonging to 40 individuals were discovered together with over 100,000 stone artifacts and convincing traces of the use of fire.

"This particular skull is only 200,000 years old, while the skulls lost in 1941 date back some 500,000 to 600,000 years. By exhibiting it we hope to rekindle interest in continuing the search for the lost skulls," said Yang Haifeng, curator of the Zhoukoudian Peking Man Site Museum.

Could the skulls still be in China?

Well-known Chinese paleolithic archaeologist Jia Lanpo (1908-2001) was respectfully known as the "Father of Peking Man." He was tormented for more than half a century by the tragic loss of the Peking Man skulls, the greatest discovery of his life. At the age of 28, Jia joined Pei Wenzhong's international team working at Zhoukoudian and unearthed a veritable treasure trove of ancient skulls and bones revealing new clues to the origins of man that thrilled the scientific world.

Jia wasn't the first to discover a Peking Man skull but his specimens were so much better preserved than any previous or indeed subsequent finds that they are of immeasurable value to scientific research.

In a co-authored book The Story of Peking Man (Oxford University Press, 1990), Jia said his life was inseparable from the Peking Man project. Unfortunately, Jia passed away on July 8, 2001 without having seen the recovery of the missing Peking Man skulls.

Jia's 61 year-old son Jia Yuzhang recently revealed an intriguing new piece of news concerning the mystery of the whereabouts of the Peking Man skulls. "A man named Wang Zhongcheng called me on April 2, 2001. He asked me to tell my then hospitalized father that all the skulls of Peking Man lost during World War II were still in China," he said.

The younger Jia recalled, "My father often jokingly styled himself the "Butler of Peking Man" and wished after death that some of his ashes could be buried at Zhoukoudian, which was listed as one of the world cultural heritage sites in 1987."

On hearing Jia Yuzhang's news, Zhang Shuangquan, assistant director of the Zhoukoudian Ancient Human Research Institute, immediately contacted Wang Zhongcheng by phone.

Wang Zhongcheng told the assistant director of the involvement of Li Zhaodong from Beijing. He related how during the War of Resistance Against Japanese Aggression (1937-1945), Li had been engaged in underground resistance work and managed to rescue the Peking Man skulls from their Japanese army captors. However Wang went on to advise that Li was presently in detention in Beijing.

However repeated requests by curator Yang Haifeng and assistant director Zhang Shuangquan to visit detainee Li Zhaodong have been turned down by the public security authorities.

Li Zhaodong's son Li Xiang offers this insight into the mystery, "My father is in jail for involvement in a fraud case. As for the Peking Man skulls, he has told me only a little of the background. What I do know is that Wang Zhongcheng who broke the news on the story was formerly engaged in intelligence work. He is a good friend of my father. During the War of Resistance Against Japanese Aggression, the Japanese army seized the Peking Man skulls that were to be sent to America. My father was working for an underground organization at that time and seized the chance to rescue the fossils from the Japanese."

Wang Zhongcheng insists that detainee, Li Zhaodong, knows the exact whereabouts of the Peking Man skulls. "Actually, they are right here in Beijing," he said.

Although their search has remained fruitless so far, both Yang Haifeng and Zhang Shuangquan express their view that "as long as there is still a glimmer of hope, we shall never give up our search for the lost fossils."

Two conflicting theories:

Trained by his late father, Jia Yuzhang has been engaged in paleoanthropological research for ten years. According to the younger Jia, there have traditionally been two popular versions in China of the story of the mystery of the whereabouts of the Peking Man skulls.

Version One: The Japanese veteran's tale and Ritan Park.

On his deathbed in 1966, a Japanese veteran revealed a secret he had kept hidden for more than two decades. This is his story:

As a medical officer with the infamous germ warfare Unit 731, he had been ordered to the Beijing Union Hospital in 1941 to undertake secret bacteriological research. Soon after his arrival, the Japanese intelligence agency seized all five Peking Man skulls. He was assigned to take care of the fossils when the agency sent them to the hospital.

When Japan was defeated in 1945 he received an order to promptly remove the Peking Man skulls from the hospital. He packed up the fossils and hurriedly buried them under an ancient pine tree in Ritan Park, approximately two kilometers east of Beijing Union Hospital. He then made a special mark on the tree.

The Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) is an academic body established under the auspices of the Chinese Academy of Sciences. It specializes in the study of vertebrate and human evolution. No sooner had the IVPP learned of the Japanese veteran's tale than researchers began to search for the fossils in Ritan Park. The marked pine tree was quickly identified but no skulls were found.

Version 2: William Foley's tale and the wreck of the Awa Maru.

William Foley, a former US Navy lieutenant, claimed in the 1970s that he was the last person to be in possession of the cased Peking Man skulls before they fell into the clutches of the Japanese army. This is his story:

He was part of the secret plan to get the relics to safety in America. In 1941 he escorted the fossils out of Beijing in two boxes. They got no further than Qinhuangdao in Hebei Province before falling into the hands of the Japanese army.

Based on Foley's tale, some researchers have speculated that after seizing the fossils from Foley, the Japanese may well have put them aboard the Awa Maru.

This was originally a Japanese commercial fishing boat and passenger ship. After the outbreak of war it operated as a hospital and supply ship under an agreement with the American government. This was however just a pretence for it was actually used for shipping loot from the occupied Asian countries back to Japan.

On April 1, 1945 the Awa Maru was torpedoed in the Taiwan Straits by an American submarine.

China made an unsuccessful attempt to salvage the wreck in 1977.

Looking back on the crating of the Peking Man skulls.

During World War II, Chinese scientists planned to have the Peking Man skulls escorted to the United States by evacuating US Marines. They were packed in two wooden crates marked A and B for the journey. But these priceless relics never made it to the safety of the American Museum of Natural History.

Paleontologist Hu Chengzhi, now 86, was Franz Weidenreich's assistant in these difficult days. It was Hu who personally took charge of the task of casing up the fossils.

"We wrapped the skulls in layers of lens paper, thick cotton, medical gauze and cardboard all with the utmost care," Hu recalled. "Each skull was placed in a separate box. Finally they were all packed into the two wooden crates."

"Besides the Peking Man skulls, the two crates also held some Upper Cave Man fossils. The latter lived about 18,000 years ago and their fossil remains were first discovered in Zhoukoudian in 1933. "The whole packing procedure took nearly two hours," Hu said.

Sadly following their mysterious disappearance all these relics remain lost to science to this day.

(China.org.cn, translated by Shao Da, November 1, 2003)