The construction of a sports field at a primary school in Qingzhou, Shandong province in 1996, revealed a secret kept for 1,400 years that went on to become one of the most thrilling archaeological discoveries of 20th century China.

Hundreds of damaged Buddhist statues and assorted debris were unearthed, allowing archaeologists, historians, scholars and artists to build a picture of ancient Qingzhou as a booming Buddhist hub during the Northern Dynasty (439-581).

See A Smile, underway at the Guardian Art Center in Beijing until March 12, traces the fruits of several findings over the years with a display of nearly 50 Buddhist figures, some of which have been restored from fragments.

Their artistic creativity exemplifies "Qingzhou style", which differs from Buddhist art found elsewhere in the country. One significant feature, as the title of the exhibition suggests, is the relaxed facial expressions and gentle smiles of the Buddhas, which must have soothed the hearts of those living through the turmoil of the Northern Dynasty era.