Restoring a royal library

Another major round composed of 105 small projects took place between 2010 and 2020, with an investment of about 600 million yuan ($82.3 million).

Yu says that one of the highlights was the restoration of the Wenjin Ge ("pavilion of a ferry transporting cultural knowledge"), a royal library that once stored giant volumes like the Siku Quanshu (Complete Library of the Four Branches of Literature), one of the largest-scale collections of ancient Chinese literature.

In the early 20th century, the pavilion's books, boxes containing the books, and bookshelves were taken to Beijing, and are now stored at the National Library of China. Losing its function, the Wenjin Ge gradually fell into obscurity and was turned into a guesthouse in the 1950s.

In 2013, as part of the second round of restoration, Yu and his team worked on the main hall for storing books, its interior decoration, and bookshelves.

Records show the hall originally had a roof of black-glazed tiles. Yu says that in traditional Chinese culture, black symbolizes water, which can extinguish fire, the biggest threat to a library. But in the late Qing period, the black glazed tiles were exchanged for clay as the government faced financial constraints.

"During renovation, we discovered they only replaced the top layer with clay tiles, and that the under-tiles had not been changed. Since the combination does not comply with building standards, we made all the tiles glazed, helping the building recover its original grandeur," Yu says.

The interiors posed a bigger challenge for restorers. Although some pictures taken by Japanese photographers in the 1930s remained, offering clues about the detailed inner finishes, they were not able to determine the exact sizes of windows, doors or the details of decoration.

"In the restoration of ancient buildings, we have to be especially cautious. I could not ascertain the sizes of windows by myself, so I looked for historical clues," Yu says.

The team discovered traces of paper hangings — patterns pasted on walls and ceilings to protect and decorate them. Since these patterns were not pasted on windows or doors, by identifying where they were not present, they were able to determine the location and size of openings.

The team then restored the bookshelves and the boxes used to contain the books. Yu says that during the Qing Dynasty, the books, boxes and the bookshelves made up a retrieval system. Through classification marks on the shelves, people could locate the boxes containing the books they were looking for, and through the marks on boxes they could find the book they wanted. As a result, when the books were relocated, the boxes and shelves had to be moved with them.

Restorers visited the National Library of China in 2015 and measured the original bookshelves and boxes so they could properly reproduce them. After two major rounds of restoration, the resort's ancient buildings and temples have been secured. In 2021, protection efforts entered a new stage of prevention, and several projects are ongoing, among them a pagoda at the Yongyou Temple, which is having its stone cultural relics and murals restored.