The game on the field is regulated by the two umpires, one of whom stands behind the wicket at the bowler's end, the other in a position called "square leg" which is about 15–20 metres away from the batsman on strike and in line with the popping crease on which he is taking guard. The umpires have several responsibilities including adjudication on whether a ball has been correctly bowled (i.e., not a no-ball or a wide); when a run is scored; whether a batsman is out (the fielding side must first appeal to the umpire, usually with the phrase "How's that?" or "Owzat?"); when intervals start and end; and the suitability of the pitch, field and weather for playing the game. The umpires are authorised to interrupt or even abandon a match due to circumstances likely to endanger the players, such as a damp pitch or deterioration of the light.
At the grassroots level, local club cricket is essentially an amateur pastime for those involved but still usually involves teams playing in competitions at weekends or in the evening. Schools cricket, first known in southern England in the 17th century, has a similar scenario and both are widely played in the countries where cricket is popular. Although there can be variations in game format, compared with professional cricket, the Laws are always observed and club/school matches are therefore formal and competitive events. The sport has numerous informal variants such as French cricket.
Crickets have a cosmopolitan distribution, being found in all parts of the world with the exception of cold regions at latitudes higher than about 55° North and South. They have colonised many large and small islands, sometimes flying over the sea to reach these locations, or perhaps conveyed on floating timber or by human activity. The greatest diversity occurs in tropical locations, such as in Malaysia, where 88 species were heard chirping from a single location near Kuala Lumpur. A greater number than this could have been present because some species are mute.
A phylogenetic study by Jost & Shaw in 2006 using sequences from 18S, 28S, and 16S rRNA supported the monophyly of Ensifera. Most ensiferan families were also found to be monophyletic, and the superfamily Gryllacridoidea was found to include Stenopelmatidae, Anostostomatidae, Gryllacrididae and Lezina. Schizodactylidae and Grylloidea were shown to be sister taxa, and Rhaphidophoridae and Tettigoniidae were found to be more closely related to Grylloidea than had previously been thought. The authors stated that "a high degree of conflict exists between the molecular and morphological data, possibly indicating that much homoplasy is present in Ensifera, particularly in acoustic structures." They considered that tegmen stridulation and tibial tympanae are ancestral to Ensifera and have been lost on multiple occasions, especially within the Gryllidae.
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".