Ruins of Xieqiqu's northern section in 1879. (Photo provided to China Daily)
She then started visiting and revisiting the Old Summer Palace. Farmers nearby had converted sections of it into farmland. In the overgrown weeds and farmland Guo searched for the remnants of hills and water systems, bridges, artificial hills, stones, building foundations and stone carvings, which were scattered among houses, pig pens and woods and on the banks of rivers and lakes.
At the end of the 1980s Guo headed a team that was designing a tourist park based on the Old Summer Palace in Zhuhai, Guangdong province. She chose 18 of the 40 viewing places, which Emperor Qianlong's artists had painted in great detail, and rebuilt them in the 580,000-square-meter park.
It opened to the public during the Spring Festival of 1997, and on March 8 that year, about 80,000 people visited it. But Guo always felt that, the park could never be regarded as representing the cultural essence of the Old Summer Palace.
She was a frequent visitor to the National Library, where she would leaf through its many archives dedicated to the Old Summer Palace, and found a gold mine of interesting material. In 2000 she proposed an archives project relating to the Old Summer Palace and planned to set up a database about the palace, starting with materials at the National Library.
Shortly before, the Beijing Municipal Administration of Cultural Heritage had started digging an archaeological site on the wasteland where the Old Summer Palace once was and invited Guo to formulate a study plan.
Guo then often rode a bicycle as she led students, among them He Yan, around the Old Summer Place searching for sites among the ubiquitous weeds. They painstakingly looked for and found the remnants of roads in the undergrowth leading to many sites that few people had reached, let alone seen. They found the steps of the palace of Shangxia Tianguang, the caves and artificial hills of Xinghua Chunguan, and the location of the island in the middle of the lake of Tianran Tuhua.
In 2006 Hengdian World Studios, China's largest TV and film production center, in Zhejiang province, built a replica of the Old Summer Palace, unleashing a public debate on whether China should rebuild the palace on its original site, and idea that found solid support.
But Guo insisted that "we should have a clear recognition of the nature of the Old Summer Palace. Currently, it is an archaeological park, a bearer and transmitter of historical information. If we replace that bearer with new buildings, we cannot see the original things".
Guo is an advocate of the ideas of her teacher Liang Sicheng on protecting cultural relics and historic sites. This approach puts a premium on protective measures that manage changes over the years and help buildings survive by bring them into a proper state of repair rather than turning old buildings into ones as new as the original ones were when they were built.
It is impossible today to make many things that would have been integral to the Old Summer Palace because the materials, tools and methods people used 150 years ago were vastly different to what people use now, Gou says.
For example, Hanjingtang, which Emperor Qianlong built for his retirement, was constructed using the finest techniques and earth that was rammed layer by layer, she says. If it was rebuilt today, people would simply use concrete, with the attendant loss of historical integrity, she says.
