Spinners get bought for turn and win matches with dip

The delivery that drops out of the air a foot earlier than expected does more damage than the one that spits off the surface.

Ask a batter which ball he actually failed to read and he will usually describe a length, not a direction. He came forward for a half volley and found himself reaching at a ball that had fallen shorter than his feet had committed to. That is dip, it happens before the pitch is involved at all, and it is the property that separates spinners who take wickets from spinners who look impressive on a highlight package.

The mechanism is revolutions and the axis they sit on. A ball spinning quickly with the axis tilted forward is being pushed downward by the air moving over it, so its flight curve is steeper than the batter's eye predicts from the release point and the early trajectory. The prediction is made in the first fraction of a second. The correction has to be made with the front foot already moving. There is no time.

Turn, by contrast, happens after the bounce, which is to say after the batter has already decided where his bat is going. Big turn beats the outside edge and produces a lovely replay. It also, quite often, goes past everything, and a ball that turns two feet from a good length is easier to leave than one that turns four inches and hits the top of off. Everyone knows this and everyone still signs the bowler who rips it hardest.

There is a coaching consequence I feel strongly about. The instruction to flight the ball is usually delivered as an instruction to bowl slower, and slower on its own is a gift. The delivery that dips is not slow; it is heavily revved and released with a high arm, which costs pace through the air only as a side effect. A spinner told to loop it who does not have the revolutions to make it drop is simply serving up half volleys at reduced speed with more time to hit them.

Which is why I distrust the way spinners are assessed on flat surfaces. When the pitch offers nothing, the bowler who survives is the one whose ball still misbehaves in the four yards before it lands, because the four yards after it lands have been taken away from him.

Watch the batter's front foot. If it goes and then stops, you have found a bowler worth paying for.