A giant scaffolding stands towering like some avant-garde art in the heart of the ancient Forbidden City.

Li Yongge, a conservation expert up on the scaffold, said he felt a rush of excitement every time he looked up from his job and caught sight of Beijing.

Below him lies the red-walled royal palaces, their golden roofs, the green woods of Jingshan Park and the white Buddhist pagoda beside Beihai Lake.

"One cannot help wondering how talented our ancestors were in designing the layout of Beijing and making the city the most beautiful one in the world more than six centuries ago," he said.

At the centre of this great work of urban planning is the Forbidden City, home to Chinese emperors of the Ming (1368-1644) and Qing (1644-1911) dynasties.

And the focus of the palatial royal complex is the Hall of Supreme Harmony, hidden behind the scaffold since January.

After two months' damage assessments by Chinese and Italian conservation experts, the Palace Museum, the administrative arm of the Forbidden City, declared last week that it would give the hall a two-year facelift starting in June.

This is the first renovation work on the Hall of Supreme Harmony in three centuries.

The hall, commonly known as the Jinluan Hall, or Hall of the Golden Throne, is the largest wooden building in the world, according to Jin Hongkui, deputy director of the Palace Museum.

It is 35 meters high, 60 meters wide, 33 meters on both sides and stands on a three-flight, 8-metre-high terrace of white marble.

The hall was also the most important building in Chinese politics from the 14th to the early 20th century. Inside, 24 emperors ascended the throne.

The nation's highest-ranking events, such as royal marriages, birthday celebrations and declarations of war, all took place in the hall, whose foundations are specially designed to fool would-be assassins tunneling into the palace on these occasions.

The foundation comprises seven layers of bricks lengthways and eight layers crosswise.

Its hall floor was paved with "golden bricks," so-called because of the pleasing sound they make when stepped on. The skills that went into making them were lost after the fall of the Qing Dynasty.

The hall's interior is largely empty, but for 14 pillars supporting the roof. The central six are gilded and painted with dragon designs while the rest are lacquered in red.

The emperor's throne, carved of sandalwood, lies in the middle of the hall. Above it is a gold painted caisson, or a sunken panel inside the ceiling. From its centre hangs a large, spherical pearl called Xuanyuan Mirror. The pearl was supposed to be able to tell right from wrong.

The hall's double-layer arched roof, which slopes down slightly to the four eaves, has 10 gargoyles nine animals and one phoenix riding on each of its four ridges. They were supposed to protect the building from evil spirits.

"Just imagine the majestic scene that unfolded repeatedly in the hall for six centuries," said Jin. "The emperor sat on his throne, the officials knelt down below his feet, kowtowed and chanted aloud 'Long Live Your Majesty,' with incense burning and floating in the air."

According to the deputy director, the vast building has never been touched, except for minor maintenance work, since it was rebuilt in 1697 after being burnt down in a fire.

Two of the four sides of its arched roof, which are covered with heavy golden glazed tiles, are sinking, said conservationists.

The glazed tiles and supporting pillars also need urgent attention, according to Jin.

"We want to restore the hall to its original glory at the height of the Qing Dynasty, during the reigns of Emperor Kangxi (1662-1722), Yongzheng (1723-1735) and Qianlong (1736-1795)," he said.

Toughest work

Of the renovation efforts, the most complicated one will be to restore the colourful paintings under the eaves, said conservationist Li.

Paintings were created directly on the wooden walls and on both the outside and inside of the eaves. While those on the inside retain their original look, those on the outside were covered with some coarse ones during a maintenance project in 1959.

Jin said researchers at the Palace Museum have found documents describing the ancient paintings on the outside walls. Conservationists are going to remove the paintings of 1959 and put up new ones that will be created on the basis of the documents and the old paintings on the inside.

The whole process will involve 13 procedures as outlined in the millennia-old documents.

The first step will involve getting rid of the 1959 paintings. This requires special care to ensure that the wooden walls are not damaged.

The next step will involve mixing the powder of bricks with the blood of pigs, applying this mixture to the part of the wooden walls to be painted upon, and then burying a thin layer of flax cloth into it.

The mixture will turn black when it dries up. After polishing its surface, conservationists will apply a layer of oil made from a special kind of tree.

Then the chief artisan will create drafts of the paintings on pieces of paper and make small holes with needles along the lines drawn on these drafts.

The paper will then be placed on the mixture of brick powder and blood on the walls and cement plastered onto the paper. This will leave white traces on the black mixture through holes in the paper. It is according to these traces that artisans will paint and fill in the colors.

"The traditional procedure to finish a painting on the walls can never be replaced by modern technologies," said Li.

"Fortunately, we have families in our renovation team who have worked for hundreds of years on these palaces. The skills that our ancestors used in building the palace have almost all been handed down," he said.

Traditional skills will also be used to make the golden glazed tiles. More than 60 per cent of the 10,000 tiles on the roof are worn out, said Zhang Kegui, also a conservation expert at the Palace Museum.

Meanwhile, cutting-edge technologies will be applied where appropriate based on the draft of the renovation plan, drawn up by experts from both the Palace Museum and the Italian Ministry of Cultural Heritage.

The fallen patches of wall coverings, for example, are to be pasted back one by one with a kind of high-tech glue.

(China Daily April 10, 2006)