A Chinese equivalent of soccer known as cu-ju started to be a popular game as early as in the Spring and Autumn through the Warring States periods. A treaties on this sport, Cu-Ju in 25 Chapters, dates to the Han dynasty and is believed to be the first of this subject in China.
Two improvements were made in the Tang dynasty to the techniques used for making the ball. Instead of two hemispherical leather pieces, the exterior of the ball now consisted of eight pieces narrowing on the ends sewed together for a rounder shape. Innovations were also inside the ball. Hair stuff was replaced by a bladder which could be inflated by blowing in air through an opening. An air ball was lighter and could be kicked higher for a goal perched on top of two 7-meter bamboo poles.
The ball game was played as a competitive sport in the Han period when two teams played each other. In the Tang era, however, a team shot from one side of a goal in the middle of the pitch to win the game by scoring more than its opponent shooting at the same goal from the other side. The Tang women also played the Chinese soccer but in a different way. Woman footballers did not go for goals but competed with each other in the height of kicks and the acrobatic moves they delivered. Women's soccer featuring this contest orientation was called bai-da.
In the Song dynasty ball handle techniques evolved from an emphasis on accurate shots to place more stress on being light in motion and sure in control. Ball making was further advanced to use twelve pieces of finely dressed leather, sewed in fine, inner stitches that were not visible from the outside. Standardization was introduced in ball manufacture for the weight and the shape. A ball was supposed to weigh exactly twelve liang (approx. 544 g) and to be "perfectly round with patchy leather pieces."