Porcelain is one of China's most famous traditions, and is something we often feature on Culture Express. Today, we'll take you to Jiaozuo City in central China's Henan Province -- birthplace of a unique form of porcelain, known as "Jiaotaici".

"Jiaotaici" is made using clay of various colors.

"Jiaotaici" is made using clay of various colors.

The clay must be repeatedly pinched to make the bubbles inside disappear. The modeling for each piece is unique, and the patterns can be seen from both inside and outside the porcelain product.

It dates back to the Tang Dynasty, and nowadays, only a handful of people know the tricks of the trade.

Folk artist Chai Zhanzhu is one of them.

Chai said, "The porcelain-making process should be strictly carried out. It's hard work, and takes a lot of time and strength."

"Jiaotaici" is made using clay of various colors.

Each piece has its own unique pattern. Just one wrong step, and the entire work is ruined.

Chai has made 34 pieces for one kiln.. but only 4 turned out OK.

As well as the high cost to production ratio, there's another problem - learning the art can take several years.

Shi Chuancehng has been making Jiaotaici since he was 17. But he still thinks he needs a couple more years to be fully trained.

Despite the laborious process, the reward is there in the end. The rarity of such works means these twisty delicate pieces can eventually command a nice price.