Mules help restorers carry supplies up to the mountain through rocky cliffs. [PHOTO BY JANG DONG AND WANG KAIHAO/CHINA DAILY]

Many approaches

A common rule in the restoration of the Great Wall today: No more than 1 kilometer in length, which means no more than five towers, are restored in one phase.

"On one hand, this ensures quality work, and on the other, if we have new theories guiding the restoration in future, we could try them at different places," Zhao says.

Shu Xiaofeng, director of the Beijing Municipal Administration of Cultural Heritage, predicts 2,700-odd meters of the Jiankou section will be restored over the next three years.

"In the ruins of Pompeii (the ancient Roman city), we still see marks of different restoration methods over the last century," Shu says.

"We might see that in Jiankou as well when using different methods."

More than 8,800 kilometers of the Great Wall from the Ming Dynasty remain today in 10 provincial-level administrative regions. In January, the national-level comprehensive conservation plan was released to guide the restoration, management and academic research of the wall until 2035.

"For those portions that have become ruins, the priority is to prevent or slow down their disappearance. Mass restoration is not suitable in such cases," according to the document.

Song from the National Cultural Heritage Administration says he expects the second phase of restoration at Jiankou to set an example for other preservation work in the country.