A cricket ball is a hard, solid ball used to play cricket. A cricket ball consists of a cork core wound with string then a leather cover stitched on, and manufacture is regulated by cricket law at first-class level. The trajectory of a cricket ball when bowled, through movement in the air, and off the ground, is influenced by the action of the bowler and the condition of the ball and the pitch, while working on the cricket ball to obtain optimal condition is a key role of the fielding side. The principal method through which the batsman scores runs is by hitting the ball, with the bat, into a position where it would be safe to take a run, or by directing the ball through or over the boundary. Cricket balls are harder and heavier than baseballs.
In Test cricket, professional domestic games that spread over a multitude of days, and almost the entirety of amateur cricket, the traditional red cricket ball is normally used. In many one day cricket matches, a white ball is used instead in order to remain visible under floodlights, and since 2010, pink has been introduced to contrast with players' white clothing and for improved night visibility during day/night Test matches. Training balls of white, red and pink are also common, and tennis balls and other similar-sized balls can be used for training or informal cricket matches. During cricket matches, the quality of the ball changes to a point where it is no longer usable, and during this decline its properties alter and thus can influence the match. Altering the state of the cricket ball outside the permitted manners designated in the rules of cricket is prohibited during a match, and so-called "ball tampering" has resulted in numerous controversies.