YINGXIAN, Shanxi -- Chinese scientists have been seeking ways to prolong the life of a 950-year-old wooden pagoda in northern Shanxi Province by another millennium, but they are still baffled over how to do it.

The Sakyamuni Pagoda in Yingxian County, Shanxi Province. [file]

The Sakyamuni Pagoda with unique architectural, religious and historical values is located at the Fogong (Buddha's Palace) Temple in Shanxi's Yingxian County, 380 km southwest of Beijing. It was built in 1056 during the Liao Dynasty, which ruled North China from 916 to 1125. China will celebrate the 950th anniversary of the pagoda on September 5.

The Sakyamuni Pagoda was made entirely of wooden parts joined by innumerable mortises and tenons in a complicated structure of brackets, without using any nails. It measures 67.31 meters in height and 30.27 meters in diameter at the base, or the height of a 20-story building today.

It is an octagonal structure of nine stories, with five visible from outside and four hidden inside. The Buddhist statues in each story and paintings on the inner walls of the first story are all works of the Liao Dynasty.

During a renovation of the pagoda in 1974, a number of sutras were found, some hand-written and others block printed. They are important materials for the study of religion and printing technology of the Liao Dynasty, as well as the political, economic and cultural developments of the dynasty.

The pagoda has undergone numerous tests in the centuries, including earthquakes, storms, lightening strikes and wars, and remained intact.

But experts warned the pagoda might succumb to another violent quake or storm, as the tower is tilting.

There have been an obvious tilt between the first and second floors and cracks in the interior wooden columns, said Chai Zejun, former director of the Shanxi Provincial Ancient Architecture Institute.

There are also 300 places in the pagoda that need repair, he said. "We are worried about the ancient pagoda's safety."

As a matter of fact, China started mulling over fixing the pagoda 17 years ago, when senior official Li Ruihuan saw the damaged condition of the pagoda and called for better protection of it. A group of renowned experts on ancient architecture, including Chai and Luo Zhewen of the State Administration of Cultural Heritage, have been conducting investigation, research and discussions on how to fix it.

But years of efforts have not turned out a solution, as all the proposed plans have pros and cons and each plan met with objections.

Experts have proposed three options: dismantle it and rebuild it with the original timber parts and technology; elevate the top three stories to fix the two bottom stories and then place the top three back to position; reinforce the damaged and twisted parts with steel structures, said Fu Xi'nian, a research fellow with the Institute of Architectural History under the Beijing-based China Architecture Design and Research Group.

"The first option will give us a new pagoda built by ourselves instead of our ancestors 950 years ago, and its historical information and value will get lost; the second one will turn out a pagoda with two new bottom stories, and what is more, can we place the top three stories exactly back to the original position? In the third option, the bottom two stories will not be as spacious and bright as today when steel structures are installed inside," he said.

"Experts haven't reached consensus, and I myself firmly oppose the first option," said Fu, who is an academician of the Chinese Academy of Engineering.

But 82-year-old Luo Zhewen, who has visited the pagoda dozens of times since 1952, is a strong supporter of the first plan.

"The most simple way is to dismantle it for rebuilding, which has been a common practice for thousands of years," he said.

Ma Bingjian, director of the Beijing Municipal Institute of Ancient Architecture Design, another advocate of the first plan, said, "To keep the pagoda is to keep the primary historical information."

In fact, the second option won the approval of the State Administration of Cultural Heritage in December 2002 when it organized a group of experts to decide on the three plans by voting, because this option was believed to cause less "disturbances"to the pagoda and be able to "preserve more historical information," according to Ma.

After that, the administration assigned the task of preparing an engineering plan respectively to Taiyuan University of Technology in Shanxi and Southeast University in east China's Jiangsu Province.

But both plans by the two universities were turned down by an experts panel who met in April this year in Shuozhou City, which administers Yingxian County.

Both plans called for huge steel structures -- Southeast University's needs 1,300 tons and Taiyuan University of Technology's needs 4,000 tons -- to be set up around the pagoda, which will inevitably cause "severe disturbances" to the pagoda and produce "unpredictable consequences," Ma said.

In addition, the plans would take as much as 90 million yuan (US$11.25 million), and about six to 10 years to repair the pagoda, he said. "That is really terrifying."

The repair project seemed to come to a dead end, but Zhou Ganzhi, former vice minister of construction,didn't think so.

"As far as I know, the research has not stopped, neither has the work of reinforcement and protection of the pagoda," said Zhou, also an academician of the Chinese Academy of Sciences and the Chinese Academy of Engineering.

"The proposed plans are not absolutely independent of each other, and some parts of them may be combined," he said.