They look like the Emperors' clocks. But are they real?

A legal dispute in New York is part of a broader questioning of the authenticity of some ornate timepieces that have come on the market from China

To stroll through the Hall for Ancestral Worship deep within the Forbidden City is to appreciate the fascination that ornate mechanical timepieces held for successive emperors of China.

Many were brought to the Ming and Qing courts as precious gifts by European ambassadors from the 17th century to the 19th. Others were later manufactured in local workshops in Beijing, Suzhou and especially, Guangzhou, in southern China.

All are marked by a stunning level of intricacy, their chimes sounding while mechanized ducks paddle, mounted figures ride their steeds and waterfalls splash down, in carefully wrought landscapes.

The hall in the Forbidden City, now a