The ball is a hard leather-seamed spheroid, with a circumference of 22.9 centimetres (9.0 in). The ball has a "seam": six rows of stitches attaching the leather shell of the ball to the string and cork interior. The seam on a new ball is prominent and helps the bowler propel it in a less predictable manner. During matches, the quality of the ball deteriorates to a point where it is no longer usable; during the course of this deterioration, its behaviour in flight will change and can influence the outcome of the match. Players will, therefore, attempt to modify the ball's behaviour by modifying its physical properties. Polishing the ball and wetting it with sweat or saliva is legal, even when the polishing is deliberately done on one side only to increase the ball's swing through the air, but the acts of rubbing other substances into the ball, scratching the surface or picking at the seam are illegal ball tampering.
In the photo, the two batsmen (3 & 8; wearing yellow) have taken position at each end of the pitch (6). Three members of the fielding team (4, 10 & 11; wearing dark blue) are in shot. One of the two umpires (1; wearing white hat) is stationed behind the wicket (2) at the bowler's (4) end of the pitch. The bowler (4) is bowling the ball (5) from his end of the pitch to the batsman (8) at the other end who is called the "striker". The other batsman (3) at the bowling end is called the "non-striker". The wicket-keeper (10), who is a specialist, is positioned behind the striker's wicket (9) and behind him stands one of the fielders in a position called "first slip" (11). While the bowler and the first slip are wearing conventional kit only, the two batsmen and the wicket-keeper are wearing protective gear including safety helmets, padded gloves and leg guards (pads).
The main objective of each team is to score more runs than their opponents but, in some forms of cricket, it is also necessary to dismiss all of the opposition batsmen in their final innings in order to win the match, which would otherwise be drawn. If the team batting last is all out having scored fewer runs than their opponents, they are said to have "lost by n runs" (where n is the difference between the aggregate number of runs scored by the teams). If the team that bats last scores enough runs to win, it is said to have "won by n wickets", where n is the number of wickets left to fall. For example, a team that passes its opponents' total having lost six wickets (i.e., six of their batsmen have been dismissed) have won the match "by four wickets".