As mentioned above, in almost all competitive one-day games, a restriction is placed on the number of overs that may be bowled by any one bowler. This is to prevent a side playing two top-class bowlers with extremely good stamina who can bowl throughout their opponents' innings. The usual limitation is set so that a side must include at least five players who bowl. For example, the usual limit for twenty-over cricket is four overs per bowler, for forty-over cricket eight per bowler and for fifty-over cricket ten per bowler. There are exceptions: Pro Cricket in the United States restricted bowlers to five overs each, thus leaving a side requiring only four bowlers.
Each Test-playing country often hosts triangular tournaments, between the host nation and two touring sides. There is usually a round-robin group stage, and then the leading two teams play each other in a final, or sometimes a best-of-three final. When there is only one touring side, there is still often a best-of-five or best-of-seven series of limited overs matches.
100-ball cricket, another form of one-day cricket with 100 deliveries per side, will launch in England in 2020. It is designed to further shorten game time and hopes to attract a new audience. It makes further changes to the usual laws of cricket, including the addition of one 10-ball over which is bowled by each side in addition to 15 traditional 6-ball overs.
Test cricket is almost always played as a series of matches between two countries, with all matches in the series taking place in the same country (the host). Often there is a perpetual trophy that is awarded to the winner, the most famous of which is the Ashes contested between England and Australia. There have been two exceptions to the bilateral nature of Test cricket: the 1912 Triangular Tournament, a three-way competition between England, Australia and South Africa (hosted by England), and the Asian Test Championship, an event held in 1998–99 and 2001–02.