Tag cricket info
Previously, in ODI, there were no fielding restrictions. The fielding captain could keep his players anywhere he wanted. Then, around the World Cup in 1996, ICC introduced the 15 over field restriction rule. Only 2 fielders were allowed outside the 30 yard circle from the batsmen for the first 15 overs on an innings. And from the 16th over, 5 fielders were allowed to move out. One more important aspect of that rule was that two fielders had to be in catching positions - 15 yards from the batsmen, till the field restrictions applied.
Now, in mid 2005, ICC - headed by one of the slowest batsman - Sunil Gawaskar came up with some changes in the restriction rule to spice up the game. The previous 15 overs of field restriction was increased to 20 over - in three blocks, called Power Play.
Power Play 1 :- Its mandatory for the first 10 overs of an innings in a one day cricket match. Only two fielders outside 30 yards from the batsmen. And two fielders have to be at catching positions, within 15 yards of on-strike batsman..
Power Play 2 and 3 :- These are two blocks of 5 overs each, also known as fielding powerplay and batting powerplay. The moment powerplay is called for, no more than 3 fielders can be outside 30 yard circle although no need to keep anyone at catching position. Generally, fielding side opts for fielding powerplay straight after first 10 overs so that they don't have to keep in-field towards the end of the innings while batting sides often like to call for batting powerplay around the 40th over mark when batsmen can try and accelerate scoring with less dangers of getting out.
Many people ask me can't batting powerplay be taken before fielding power-play? why not, but for that to happen, fielding side will wait till batting PP is taken and in most probable case, they'll bowl last 10 overs with just 3 fielders on baundary.. not nice, and hence they do it as soon as they can.
Case of less than 50 overs innings :-
Sometimes, due to rain or other factors, ODI innings are shortened from usual quota of 50 overs. In that case, powerplay overs are reduced in following format..