Unlike Test cricket, the fielders are spread out to save the runs in the limited overs cricket. The powerplay rule (Restrictions on the placement of fieldsmen), along with a number of other factors, contributed to the big scores (250+) in modern One Day Internationals.
Mandatory powerplay (1-10 overs)
In an uninterrupted match (i.e. 50 overs), the first 10 overs of an innings will be a mandatory powerplay. During the mandatory powerplay only two fielders are allowed outside the 30-yard circle and there must be a minimum of two stationary fielders in catching positions (15 yards) measured from the striker’s end at the instant of delivery.
When a fast bowler is bowling the two stationary fieldsmen may be permitted to stand deeper than 15 yards provided only that they are standing in slip, leg slip or gully positions.
The second powerplay is a block of five overs: which will be at the discretion of either of the batsmen at the wicket. It is often referred to as the batting powerplay. During batting powerplay overs, only three fielders are allowed outside the 30-yard circle. There are no requirements about close catchers in a batting powerplay.
In an innings of scheduled duration of between 41 and 50 overs, the batting powerplay may not be completed later than the 40th over. Should the batting side choose not to exercise their discretion, their powerplay overs will automatically commence at the latest available point in the innings (e.g. in a 50 over innings, this will begin at the start of the 36th over).
During the non-powerplay overs (35 overs in a 50 over game), no more than four fielders shall be permitted outside the fielding restriction area (the 30-yard circle).
When the batting team's number of overs is reduced, the number of powerplay overs shall be reduced. In the event of an infringement of any of the above fielding restrictions, the square leg umpire shall call and signal ‘No Ball’.
Fielding restrictions evolved through the 1970s, notably in World Series Cricket, and were first introduced in ODIs in 1980 in Australia. The most common rule was for only two fieldsmen to be allowed outside the circle in the first fifteen overs, then five fieldsmen allowed outside the circle for the remaining overs.
The powerplay moniker was introduced by the International Cricket Council in 2005, when the fielding restrictions were split into three blocks: the mandatory ten overs at the start of the innings and two further five-over powerplays with the bowling team being able to choose the timing of both. In practice though, both were generally taken as soon as possible, effectively leading to a single block of 20 overs of fielding restrictions. To counter this, in 2008, the batting team was given discretion for the timing of one of the two powerplays.
From October 1, 2011, the ICC brought additional changes to the bowling and batting powerplays. Under the new rules, in a 50-over match, neither powerplay may be taken before the start of the 16th over and both must be completed before the commencement of the 41st over, so overs 11 to 15 and 41 to 50 cannot be powerplay overs. Should either or both teams choose not to exercise their discretion, their powerplay overs will automatically commence at the latest available point in the innings (e.g. in a 50-over innings with one unclaimed powerplay, it will begin at the start of the 36th over).
On October 29, 2012 The International Cricket Council made further amendments on powerplays, reducing the number of blocks of Powerplays from three to two.