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.
According to the social historian Derek Birley, there was a "great upsurge of sport after the Restoration" in 1660. Gambling on sport became a problem significant enough for Parliament to pass the 1664 Gambling Act, limiting stakes to £100 which was, in any case, a colossal sum exceeding the annual income of 99% of the population. Along with prizefighting, horse racing and blood sports, cricket was perceived to be a gambling sport. Rich patrons made matches for high stakes, forming teams in which they engaged the first professional players. By the end of the century, cricket had developed into a major sport which was spreading throughout England and was already being taken abroad by English mariners and colonisers – the earliest reference to cricket overseas is dated 1676. A 1697 newspaper report survives of "a great cricket match" played in Sussex "for fifty guineas apiece" – this is the earliest known match that is generally considered top-class.
Limited overs cricket is always scheduled for completion in a single day. There are two types: List A which normally allows fifty overs per team; and Twenty20 in which the teams have twenty overs each. Both of the limited overs forms are played internationally as Limited Overs Internationals (LOI) and Twenty20 Internationals (T20I). List A was introduced in England in the 1963 season as a knockout cup contested by the first-class county clubs. In 1969, a national league competition was established. The concept was gradually introduced to the other leading cricket countries and the first limited overs international was played in 1971. In 1975, the first Cricket World Cup took place in England. Twenty20 is a new variant of limited overs itself with the purpose being to complete the match within about three hours, usually in an evening session. The first Twenty20 World Championship was held in 2007. Limited overs matches cannot be drawn, although a tie is possible and an unfinished match is a "no result".