Dale Steyn's devastating spell of reverse swing bowling on the fourth and final day of the second Test against Australia at St George's Park last week ripped the heart out of the tourists' batting and led the home side to an emphatic 231-run victory, which atoned for the similarly heavy 281-run defeat in the opening Test.
Like many sporting phenomena, reverse swing materialised from time to time, by chance, as far back as the 1950s. But bowlers were unable to understand it, let alone recreate it. Reports exist of the ball swinging the "wrong way", but it wasn't until the late 1980s and early 1990s that concerted efforts and experimentation took place to unravel the mystery.
Imran Khan admitted 20 years ago that bottle tops were used to scratch one side of the ball and various players – from various countries – admitted after retirement that a variety of lotions, from sun cream to Vaseline, were used to enhance shine for conventional swing.
For reverse swing to take place, the two sides of the ball must be in completely opposite conditions. One must be dry and rough, the other smooth and shined well enough to please an army drill sergeant with a combination of saliva and sweat. There are, of course, few places on a cricketer's body from which sweat can be harvested in public without it containing sun cream.
Similarly, many cricketers chew gum or eat energy-boosting sweets during play. The sugar in their mouths can act as an artificial "varnish" when applied to the ball and polished vigorously.
The shiny side of the ball
The aerodynamics of conventional swing bowling result in the shiny side of the ball creating less friction in the air and therefore travelling faster towards the batsman. With reverse swing, the rough side of the ball travels through the air faster because of the weight of the moisture on the shiny side. At least, that is the cricketers' theory. Aerodynamicists have much to add – but it is irrelevant to the cricketer. They just want it to work.
Cricket lovers may already have forgotten that, while St George's Park may have been the most spectacular display of reverse swing, it was not the first this season.
At Kingsmead in Durban, Jacques Kallis's farewell Test match looked to be turning sour with the tourists cruising to 189-1 on the first day. Dale Steyn had figures of 0-49.
The following day, with favourable atmospheric conditions and a ball that finally started yielding to all the work done on it the day before, Steyn ripped through the top and lower order to finish with 6-100 as India crumbled to 334 all out.
The process of "preparing" the ball for reverse swing owes much to luck and begins when (hopefully) one side of the ball begins to show more natural wear and tear than the other. Some teams have even been known to bowl a few full tosses and long hops at the batsman to concede a few sixes that land on concrete stands.
Rough treatment
This "ageing" process is then exacerbated by throwing – or even dropping – the ball on to abrasive parts of the ground, such as the dry ends of old pitches. And the most skilful fielders have perfected the art of throwing the ball like a Frisbee, with the seam horizontal rather than vertical, thus ensuring that it lands on the rough side.
Every member of the team must be aware that Operation Reverse Swing is under way, but not all players can take an active role. Some, for example, are simply too sweaty and cannot be trusted not to "leak" on to the rough, dry half of the ball. Fast bowlers, of course, are perennially sweaty, which is why they often wear absorbent wristbands and only receive the ball from a "dry" fielder at the top of their run-ups.
The laws of the game and the powers of umpires have been significantly strengthened to deal with ball tampering and the emphasis has been placed on the use of anything "artificial" to alter the "natural state" of the ball.
Fielding sides can be sanctioned and have penalty runs imposed on them if, in the opinion of the umpires, they are regularly throwing the ball "on the bounce" to the wicketkeeper. In addition, the umpires check the condition of the ball after every over.
Close to 30 cameras are used in modern-day television productions, of which as many as half enjoy the freedom to "roam" between deliveries. There is nothing a director enjoys more than a "scoop", no matter what his national allegiance.
Beady eye
The ball was followed in unrelenting detail during the game in Port Elizabeth and will be again during the third Test at Newlands in Cape Town beginning on Saturday. There is nowhere on the ground where skulduggery can be concealed. The umpires even retain the ball during drinks and meal breaks.
Australia's troubled opening batsman, David Warner, suggested this week that the home side were up to no good in PE. He suggested that AB de Villiers had been rubbing the ball into the ground. Proteas team manager Dr Mohammad Moosajee described Warner's comments as "disappointing, disparaging and slanderous".
Far more tellingly, Australian fast bowler Ryan Harris dismissed emphatically any criticism of the Proteas attack: "We were all trying to do the same thing. South Africa just did it much better than us."
Ironically, Newlands has a history of providing enough seam movement and conventional swing for the fast bowlers not to have to worry about employing reverse gear. But if they do, it would appear the home side are reversing considerably better than their opponents at the moment.