The stolen bronze mirror. [File photo]

Police in Gansu Province are offering a 20,000 yuan (US$2,857) reward for information leading to the arrest of the thieves who stole an ancient bronze mirror from a Dunhuang museum last month.

There have been no major breakthroughs in the case, the Lanzhou Morning Post reported today.

An insider told the newspaper that detectives had checked every antique market in Dunhuang but had failed to obtain any information.

Detectives are having difficulties with the case because the museum cannot give an accurate time for the theft. Museum staff failed to protect the mirror and did contact police immediately the theft was discovered, the newspaper said.

The mirror, 11 centimeters in diameter and a mere 3 millimeters thick, is rated a Class-A heritage cultural artefact under national protection.

The Chinese characters Wei Zhi San Gong, meaning "among top ranking officials," are inscribed on the back of the mirror.

A number of bronze mirrors have been unearthed in the Hexi Corridor region in Gansu Province in recent years, but the stolen mirror was one of the best preserved.

Three other ancient bronze mirrors of lesser value were also stolen at the same time.

(Shanghai Daily September 9, 2008)