Archaeologists have found about 3,000-year-old toy balls in a cemetery near the city of Turpan in northwest China.
The largest ball has a diameter of 9.2 centimeters.
These are the oldest traces of a ball game ever found in Eurasia.
The oldest playing balls in the world come from Egypt and were made 4,500 years ago.
The oldest playing balls on the American continent are about 3,700 years old.
For a long time, it was thought that ball games were not invented until much later in Europe and Asia.
They are believed to have been invented 2,500 years ago in Greece and 2,200 years ago in China.
Now it appears that this happened longer ago.
Chinese, German and Swiss researchers write in the
Journal of Archaeological Science: Reports
that they found three leather balls with diameters of 7.4 to 9.2 centimeters.
What kind of game was played with this is still unknown.
According to the researchers, it is clear that balls were played to get exercise and to train soldiers.
One of the graves where the balls were found belongs to a horseman buried with a bow.