Sending a left-hander up early is the cheapest tactic in the tournament

One promotion in the batting order can make an opposition captain retire his best powerplay option before the fourth over.

A right-arm off-spinner opening the bowling to two right-handers is one of the more comfortable jobs in this format. He turns the ball away from the pads, he can bowl a flat line at off stump with a deep point and a mid-off, and if the batter tries to hit against the spin over midwicket he is taking on the turn with a fielder waiting.

Now put a left-hander at the other end. The angle inverts completely. The ball is turning into the pads, which means the leg-side field has to change, which the captain cannot fully do because of the powerplay restriction. Suddenly the safest area for the batter is straight down the ground and over midwicket, with the spin, and the spinner has to bowl wider and flatter to avoid it, at which point he is not really an attacking option any more.

That is the whole tactic. It costs nothing. You are not asking a batter to play differently, you are asking him to bat somewhere different for a few overs.

And it is not only about that first spinner. Once the promoted left-hander is in, the opposition's whole plan for the powerplay wobbles. The seamer who was going to attack the stumps from over the wicket now has an angle problem. The captain has to decide whether to burn an over of his best bowler on a matchup that no longer favours him, or hold him back and give up an over to somebody weaker while the field restrictions are still on. Neither option is good, and forcing an opposition captain into a choice between two bad options in the fourth over is worth more than most of the things teams spend money on at the auction.

The cost is real though. The batter you promote is usually a middle-order player who is now facing the new ball, which is a genuinely different skill, and the batter you demote arrives at a phase he does not know. Do it too often and you have a side where nobody has a settled role, which shows up in the fifteenth over when somebody has to make a decision under pressure and does not know what his job is.

So it should be a weapon, not a habit. Use it against the sides that lean on an off-spinner up front. Leave it alone against the ones with two left-arm quicks, where you will just be creating a mismatch for them.

Simple, cheap, and considerably underused.