The difference between Nagpur and Nottingham
Nottingham, August 2015. Stuart Broad seams the ball off a green pitch and runs through Australia, who are bowled out for 60. Their innings lasts all of 18.3 overs.
Nagpur, November 2015. R Ashwin and Ravindra Jadeja spin South Africa out for 79 on a second-day surface riddled with cracks and frequently throwing up puffs of dust. Their innings lasts 33.1 overs.
What's the difference?
At Trent Bridge, Broad keeps the seam upright, and keeps everything in the corridor outside off stump. Some balls move in, others leave the batsman. It is hard to tell if Broad himself knows which way the ball will go.
At the VCA Stadium, Jadeja fires the ball into the surface, in line with the stumps. The ball sometimes spits away from the right-hand batsman and at other times hurries through with the angle - very often, both outcomes come about with Jadeja spinning the ball with the same force and the same angle of rotation.
What's the difference?
"What's the difference?" is often India's retort when anyone questions their desire to play on pitches that turn sharply from day one. Every player or member of their support staff, when sent out for press conferences during home Tests, brings up teams preparing greentops when India go abroad. Why then, they ask, should India not prepare turners at home?
Ashwin did the same on Thursday, except, instead of using one of India's away Tests for the comparison, he brought up the Trent Bridge Ashes Test.
"Swing, seam and bounce, two days match over at Trent Bridge, I don't know what's that about. What's the problem with spin and bounce? It is good, even spin and bounce, isn't it? It is about skill for batsmen to play it and counter it."
There is nothing wrong with turn and bounce, per se. A pitch offering seam movement and another offering sharp turn are equally good surfaces, provided the pace and bounce are consistent. But there is a difference between the kind of assistance England's seamers enjoyed at Nottingham and the kind of help India's spinners got in Nagpur.
At Trent Bridge, Australia's batsmen were unsure which way the ball would move after it pitched. But they could trust how quickly it came to them, and the extent of its bounce. Both were true, and anything straying from a good line or length could be put away safely. In Nagpur, in addition to not knowing how much, and if at all, the ball would turn, South Africa's batsmen - and indeed India's - seldom knew if the ball was going to stop on them or skid through quickly, and whether it would jump or keep low.
On most seaming pitches, batsmen face a time-honoured challenge of footwork and compactness: to go fully forward or back, and play late and close to the body, to minimise the damage that the seaming ball can do. It is difficult, but not impossible. The challenge on good spinning pitches is similar: good footwork to go forward or back, soft hands in defence.
On a surface such as the one in Nagpur, driving could be fraught with risk even if you got reasonably close to the pitch of the ball - as Shikhar Dhawan discovered during India's first innings. Even if you went deep in your crease to a short ball, it could stop on the pitch and surprise you - as AB de Villiers found out against Jadeja.
A green, seaming pitch often gets better to bat on. That is why openers are advised to give the first hour to the bowlers. In Nottingham, the entire Australia line-up lasted just beyond that first hour. When England batted, the pitch had lost quite a bit of its initial freshness. Australia's bowlers, moreover, failed to land the ball as consistently in the channel or as consistently on the seam as Broad did. England replied with 391.
A pitch that turns from the first day only gets worse to bat on. Since it is dry at the start, with no grass on its surface, there is nothing in the pitch to prevent it from crumbling rapidly under the sun and under constant bombardment by cricket balls and feet.
This is why the classic subcontinental pitch starts out firm and flat. On day one, there is consistent pace and bounce, even if not in liberal measure, and a bit of spin. Fast bowlers can expect the new ball to swing for a short while, and the old ball to reverse, and in most cases get edges to carry to the keeper and slips. But the first two and a half days, by and large, are good for batting. First-innings totals are often big, but that is no guarantee of a win or draw. By day four, wear and tear could leave the pitch behaving like the Nagpur pitch did on day one.
Such a pitch produces multi-dimensional cricket, rewarding both sound defensive batting and sound attacking batting, quality quick bowlers blessed with either pace or swing, particularly reverse, and accurate spinners, particularly those who can beat batsmen in the air.
A pitch such as Nagpur - or Mohali during the first Test - produces cricket that is predictable and repetitive. Spinners fire the ball in quick, batsmen hope they get enough bad balls to score from before the inevitable good one comes along, and 200 is often a match-winning first-innings total. The entire match is often done and dusted - pun intended - within three days.
Who wins in such a scenario? Often it is India, but the philosophical argument against such pitches extends far beyond the exaggerated home advantage they can offer. The argument against such pitches would remain the same even if India prepared such pitches against visiting teams with quality spin attacks - such as the current Pakistan side or the England of 2012 - and the three-day finishes also happen to be exciting.
The odd shootout in a dustbowl can often invigorate a dull series, and occasionally a batsman might play an innings that is remembered decades down the line - such as Sunil Gavaskar's 96 in his farewell Test. But India's insistence on pitches that turn from day one is threatening to produce a monoculture of dustbowls and nothing else. It has not happened yet - Bangalore produced a good pitch for the second Test - but it seems to be heading in that direction. If that happens, it will only limit the otherwise vast possibilities of Test cricket in India.
Russell Domingo, South Africa's coach, refused to criticise the Nagpur pitch - and gave credit to India's spinners for bowling with far more control than those from his side - but seemed to hint at the loss of those vast possibilities while describing how difficult batting had been, for both sides, during this series. He harked back to perhaps the greatest Test match played on Indian - or any - soil: Kolkata, 2001.
"I was watching some cricket on YouTube last night, India against Australia, with Dravid getting 180 and VVS getting 281. Those were great wickets to bat on. These haven't been, and the statistics show that no one has got runs. And that is the difference."
India's last home win over South Africa before this series, in 2010, also came at the Eden Gardens. The win was achieved with a big margin - an innings and 57 runs - but only at the culmination of an exhausting effort of will and skill from pretty much all of their players.
South Africa batted out 131.3 overs in their second innings in a dogged effort to save the match. Hashim Amla made centuries in both innings, and was still undefeated when Harbhajan Singh ended a stubborn last-wicket partnership with a mere nine balls left to play. It was Harbhajan's eighth wicket of the match, but it took him 72.3 overs of probing, untiring offspin to get them. There was turn and bounce on that pitch, but good batsmen could survive and make runs. India's two fast bowlers, Zaheer Khan and Ishant Sharma, played a big part in the win too, sending down 71 overs across the two innings and picking up seven wickets between them.
It was a Test match that had tested everyone. India won, but so did Amla, his reputation as a world-class batsman greatly enhanced. So was South Africa's reputation, for having fought to within nine balls of saving a Test they seemed to have thrown away on the first day. The spectators got to watch a variety of skills being displayed over a full five days.
Now, if India fulfill expectations and wrap up the Nagpur Test on Friday, they will have won a Test series against South Africa for the first time since 2004. They will have ended their opponents' nine-year unbeaten run away from home. But they will not have done it, and would not have had the chance to do it, by playing outstanding cricket. When they ended Australia's 16-match winning streak in 2001, they did it on good pitches. It felt a lot more special.
Karthik Krishnaswamy is a senior sub-editor at ESPNcricinfo