Five years ago, a documentary series titled "Masters in Forbidden City" was released in China and soon became a hot-button topic on social media, bringing the profession of cultural relic restoration into the public spotlight.

Given China's long history and rich collections of ancient artifacts from various dynasties, it takes meticulous hands, years of experience and a thorough understanding of history to become a qualified restorer. As backstage heroes, many of them have dedicated their lives to preserving national treasures.

Located by a massive lake and shaded by trees, the Hubei Provincial Museum occupies a corner of tranquility in the bustling city of Wuhan. Inside, Fang Guorong, 62, and Fang Chen, 32, jointly lifted a 12-kg bronze object in an attempt to restore a huge and ancient bianzhong, or chime bell.

The Fangs, father and son, both work as relic restorers at the museum. The 150-kg chime bell they were taking care of is the biggest and heaviest one preserved here, having been unearthed from a 2,500-year-old tomb in Suizhou, Hubei, in 2009.

Chime bells are a percussion instrument that became prevalent in China from the Western Zhou Dynasty (1046-771 B.C.). The country's largest set of chime bells ever unearthed was found in 1978, also in Suizhou, in the tomb of Marquis Yi, a ruler of the ancient Zeng State. The set of 65 chime bells has been a key highlight of the various collections of the Hubei Provincial Museum.

Fang Guorong has been engaged in the restoration of bronzeware for more than 40 years, since he became a staff member of the museum. He has participated in various chime-bell restoration projects and has served as the technical director in various duplicate projects.

The process of chime bell restoration -- including designing, wax mold-making, investment casting, welding, polishing and antique finishing -- demands both skill and patience. Fang Guorong enjoys it, cherishing every touch of the bells as part a dialogue with craftsmen of the distant past.