Ball tampering

In the sport of cricket, ball tampering is an action in which a fielder illegally alters the condition of the ball. The primary motivation of ball tampering is to interfere with the aerodynamics of the ball.

Under Law 42, subsection 3 of the Laws of Cricket, the ball may be polished without the use of an artificial substance, may be dried with a towel if it is wet, and have mud removed from it under supervision; all other actions which alter the condition of the ball are illegal. These are usually taken to include rubbing the ball on the ground, scuffing with a fingernail or other sharp object, or tampering with the seam of the ball.

Generally, the purpose of altering the state of the ball is to achieve more favourable bowling conditions. Examples of ball tampering would include a fielder applying a substance, such as lip balm or sweetened saliva, to shine one side of the ball or pick the seam of the ball to encourage more swing. Conversely, roughening one side of the ball by use of an abrasive or cutting surface (such as boot spikes or bottle caps) is also ball tampering.

Using spit and/or sweat is common and, for practitioners of swing bowling, integral. The moisture gained from spit or sweat when combined with polishing, smooths out one half of the ball which in turn allows air to pass over one side of the ball more quickly than over the other. When bowled correctly, a bowler can get the ball to move from one side to the other through the air. Also, it is common for bowlers to rub the ball against their clothing to dry or polish it, as seen in most cricket matches.

The umpires are responsible for monitoring the condition of the ball, and must inspect it regularly. Where an umpire has deemed a fielder to be guilty of ball-tampering, five penalty runs are awarded to the batting side, and the ball must be immediately replaced. The replaced ball is normally chosen by the umpires, in which case the ball chosen should match the condition of the previous ball (before tampering) as closely as possible. Depending on additional agreements laid out before the beginning of a series of matches, the batsmen may be instead permitted to choose the ball from a selection of balls in various stages of use.

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