Photo taken to show the plaque hanging Fuwang Chamber. [Photo/Weibo]

As a seven-year refurbishment project comes to an end, the Fuwang Chamber inside the Emperor Qianlong's Imperial Garden, at the northeastern corner of the Forbidden City, is expected to be unveiled to the general public in 2020, experts say.

The three-storey Fuwang Chamber, also known as the "Mystic Chamber" because of its sophisticated yet delicate building style, gives the visitor a sense of loss and confusion.

Founded in 1772, it functiond as a residential and entertainment place for Emperor Qianlong during his twilight years.

In 2001, the Palace Museum singed a contract with the World Monuments Fund in the United States to start the restoration project on the Qjuanqin Studio in the Emperor Qianlong's Imperial Garden. And five year later in 2006, the projects expand its restoration area to the entire imperial garden, Fuwang Chamber is included.

"The interior settings almost remain the same after more than two hundred years have passed. This is because that the Emperor Qianlong once issued an edict that only overlord or the father of the emperor has the privilege to live here and the layout of the chamber cannot be changed forever. However, Emperor Qianlong himself did not expect that no overload has ever lived here afterwards," project general engineer Wang Shiwei said.

"The decoration materials in the chamber are extremely valuable and many are solely utilized here. For instance, the wooden materials adopted the techniques of inlay and package. The ancient carpenter inlaid nanmu, a Chinese timber with rosewood to firm the chamber structure on the hand, to showoff the nobility and grace of imperial architecture," said Wang.

Meanwhile, a Sino-US technological operation is an example of the worldwide architecture circle.

"American scientists have advanced technology and ideas. They conduct a careful stuffy on the details of those ancient building that need repairing and start the project in the principle of a combination of tradition with modern technology," Wang said.

"For another example, people may notice the ancient paper windows at first sight when entering the chamber. But we have installed double-glazing windows in reality and the paper is fixed between the windows. Compared with the metal floor-to-ceiling ancient paper windows in the past, the current ones are not only environmental friendly but can shed the light and keep the interior cool," Wang added.