That makes Tongguan kiln porcelain valuable for studying society and culture of the Tang period, experts say.

Tongguan was the birthplace of the country's multicolored porcelain and the Tongguan kilns can be regarded as an export-oriented industrial cluster, with its products sent to nearly 30 countries and regions, reaching as far as South Asia and northern Africa, according to Qu Wei, curator of the Museum of Tongguan Kiln Porcelains in Changsha.

Lower prices, unique multicolored underglaze painting and foreign cultural elements integrated into the shapes and decorations made the items produced at the Tongguan kilns a favorite for export during the middle-to-late Tang era, Qu says.

The Tongguan museum preserves more than 160 items of 9th-century porcelain recovered from an Arab boat that left China during the Tang Dynasty, but later sank in Indonesia's Java Sea, referred to as the Batu Hitam shipwreck.