It’s now time to talk about reverse swing. No, it’s not the latest dance craze from California. It’s a relatively new phenomenon in cricket that entails the ball doing funky things previous unknown in the laws of physics. Unlike in baseball, the fielding team gets to keep the ball, even if it gets hit into the crowd. What this means is that the bowlers (pitchers) can “work” on it.

When you first get a cricket ball it’s shiny on both sides of the seam (a seam on a cricket ball, like the Equator around Earth, runs straight and not crooked). Conventional swing can be obtained by allowing one side of the ball to be roughened up naturally through hitting the bat or abrading on the grass and dirt, while you polish the other. Naturally, air would move more evenly over the smoother side of the ball, causing the ball to curve through the air in the direction of the smooth side. Here’s an example of the incomparable South African Dale Steyn manipulating the ball in the air and off the pitch:

However, recent bowlers have discovered that by making the rough side even rougher, and keeping that side particularly free of sweat or any other moisture, and holding the ball slightly differently, the sphere after a while may do something very strange: it bends in the opposite direction. This is reverse swing and it’s driving batsmen crazy.  Now they don’t know whether to play the ball for normal swing or not. The result, as Australia discovered against Pakistanis Wasim Akram and Waqar Younis in 1995, can be embarrassing:

Nobody’s yet quite sure how it works, or what combination of the relative age of the ball, its scuffed-up-ness, the skill of the bowler, humid conditions of the ground, or abrasiveness of the pitch can make it do these magic things in the air. But it does, adding further mystery to the art of fast bowling.