It's possible to make changes to your field without actually moving the fielders.
Tradition dictates that changing a field involves moving a fielder from one position to another. Mid off may go to deep mid off in defence or silly mid off in attack for example.
However, there is great scope within each fielding position for the tactically aware bowler, captain or fielder to exploit to their advantage. It means forgetting about thinking of any position as a static point. Instead it's a large area. Mid off, for example, could be up level with the stumps or three quarters of the way to the boundary. They could also be fairly straight or quite wide.
It's important to know this mainly because these subtle changes can be very effective in slowing scoring and taking wickets. Good batsmen also understand this so they can see how the opposition are trying to get them out.
You can split theses type of tactics into three general areas:
1. Close fielding
Slips, gulley, short leg and other close fielders should all be aware of the clues about how far from the bat to stand. The obvious part is the speed of bowling and pace of the wicket. Generally the faster either of those factors, the further back you can stand as the ball carries extra distance.
Slip fielders can get their cue from the wicketkeeper in the normal way: First standing slightly further back than the keeper and second about level. Gulley can be more difficult as the position can cover a very wide area from fifth slip to backward point. You need to decide if you are there for the mistimed cut or the thick edge off the top of the bat. In the former case you will be further back. You also need to take into account the technique of the batter. The more open faced they play the straighter you will need to be (with the slips possibly wider than usual).
Leg side close fielders and off side fielders in front of the wicket need to be an excellent judge of how far the ball will carry to them. This can be difficult at leg slip or leg gulley especially. Again the decision on how close depends on bowler pace, wicket pace and whether you are there for an attacking of defensive shot.
All close fielders will need to be closer for batsmen who play defensively with soft hands than they do for those who go at the ball at lot harder in defence.
2. In fielding
In general the in fielders are positioned to save batsman scoring singles first and boundaries second. Where your fielders stand depends on how fast the ball is coming off the bat. The faster it arrives the further back the fielder can stand.
Batsman can take advantage of this through tip and run tactics, drawing a fielder in until they are too close then hitting it past them before they have time to react. Because of this it's a good idea that all in fielders on the same side of the wicket stay in line with each other as a way of checking positioning. If one fielder chooses to adjust for a certain batsman, the rest must follow suit, ideally through the bowler and captain.
Speaking of batsman, if one batsman has a favourite shot it's possible to move the two closest fielders closer together, cutting off the gap. It's also worth trying to place a fielder deliberately a little too deep sometimes. This can backfire but is useful against the player who likes to try and hit over the top.
Another exception to the general in fielding rule is when you are playing in a match with fielding restrictions and a fielding circle. Here you will often find fielders posted on the very edge of the circle, too far back to save a single but not permitted to go outside it to save the boundary properly.
3. Out fielding
The outfielders are generally deployed to save boundaries and take catches in the deep. Every schoolboy cricketer is aware that they should be on the boundary to save the embarrassment of the ball going over their heads but landing within the boundary.
This is sound advice most of the time, although bringing a fielder in 10 yards from the boundary is a risky but legitimate tactic against the batsman with ego enough to think they can clear them. You can also station fielders some way in on longer boundaries, especially when it's clear the batter will not hit that far.
On the other hand, very short boundaries are more difficult. You may often find it worthwhile to move an in fielder to the boundary to save the four and give one away. On balance it might work out costing less than having a man in an orthodox position.
Just like the in field, the technique of the batsman also needs to be taken into account. Two players may get the same ball and perhaps even play the same shot but the ball rarely ends up in the same place. It may be obvious to say it, but adjust positions to be where the ball is more likely to go, especially if it is in the air at the time.
Finally, it's important to remember who is in charge of all this micro-field changing.
The captain should always have final say as they are looking at the bigger picture and have overall command on the field. Captains usually work with their bowlers; sometimes even letting them set their own field. Fielders should keep a close eye on both.
Experienced fielders can also make these micro decisions based on what they see. Care must be taken before taking a decision independently though. It may be worth confirming with the skipper until you can build up his trust in you.
Wherever you are fielding, remember not to let yourself slip out of position accidentally and only move based on sound tactical knowledge or the instruction of your captain.
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