A cricket field is a vast place. To protect it with just nine fielders is a fascinating exercise. It involves intricate knowledge of the angles the ball is likely to take when played against a particular kind of bowling. This is, arguably, a bit more straightforward with the ball seaming than when it is spinning. Throughout this series, never mind the pitches earlier, India have made it seem like South Africa are batting against 18 fielders, and not nine.
TV doesn't do justice to the setting of fields and Virat Kohli sets them painstakingly. When the fast bowlers began the innings, his concern was on the slips. For some reason he kept shuffling them. Ravindra Jadeja began at second slip, Kohli himself moved in there in the second over, and after a few chops and changes it was time for spin. Now came the spectacle. Every fielder was moved a little here, a little there. It was almost like a fine driver checking the rear-view mirror, the side-view mirror, the handbrake and the gear before turning the ignition.
India maintained a deepish mid-on and mid-off, a short cover and a deepish cover for left-handers against R Ashwin. Proper in-and-out fields were used when a partnership was on or when a specialist batsman was batting with the lower order. If the bowlers are accurate - which Ashwin and Jadeja have been - it is a suffocating field. If you hit firmly down the ground, there is no single as Temba Bavuma discovered first ball from Ashwin. It is also riskier to try and clear those men with chip shots. The pitches are slow as well, so it is hard to time the ball and place it wide of those men patrolling the straight field.
Ashwin's second over, now with Dean Elgar on strike, brought that deepish cover into play. Put yourself in the batsman's shoes. Elgar has fought hard for long periods without much success. Imagine what a leap it must be then to try and cover drive India's best spinner without getting to the ball on the half-volley. Elgar managed to do so, using his hands to keep the ball down, and managed to beat Kohli at short cover too, but found the man behind him. You take all the risk, you time the shot to perfection, you pierce a gap and yet you don't get a run.
If you then put together a partnership, like Hashim Amla and Faf du Plessis did in Nagpur, the close-in fielders remain. The only release of the pressure comes at single-saving positions, and if you now play the perfect shot through the infield, you still get just the one. That sweeper cover and deep midwicket or deep square leg have always been waiting, throughout the series.
Indian captains all learn these tricks, but Kohli has not wasted any time doing so. In his first home series as captain, he has got all the angles right and choked the life out of South Africa's batting. Just like Kumar Sangakkara's and Mahela Jayawardene's fields, you couldn't really say India were defending even when they had men back. South Africa, on the other hand, have opened up the singles while trying to keep the runs down and conceded boundaries when looking to attack.
Only the genius of AB de Villiers could best these fields. Jadeja bowled with point, short cover, deepish cover and mid-off to go with the catching men. Kohli, at short cover, was straightish, leaving a small gap between himself and mid-off. De Villiers found that gap. But when Amla drove at a similar delivery, he could only hit it to the left of Kohli and deep cover came into the picture again.
De Villiers played the angles well and got maximum reward for minimum effort. The others were forced to find not just one but two gaps if they wanted any runs. Amla couldn't, against Jadeja; Elgar couldn't, against Ashwin.
Amla got nothing to score. Ashwin even left cover open for him, packing the leg-side field, where the ball would go with the turn, but Amla couldn't get the ball away. He waited and waited, and then went to play a cut to one that was perhaps was not short enough. It was a shot brought about by tight fields and accurate bowling, a natural consequence when all your good shots are going to hand.
Du Plessis, who came just after Amla, has seen it all during the series. He has not got one loose ball and when he buckled down in Nagpur he kept hitting to field. Perhaps that was why he decided funky was the way to try to upset the Indians' stranglehold. It didn't work. It has been the story of the series.
Of course both teams have only nine fielders, and it is the bowlers' accuracy and skill - also the slowness of the pitches and the scrambled minds of the batsmen - that allow Kohli to both attack and defend one part of the field at the same time. Ashwin must have bowled about 10 bad balls all series. And with Jadeja those deepish mid-on and deepish mid-off make even more sense: you hit hard, you don't get a run; you hit softly, Jadeja is so quick he doesn't let the ball past him. Every dot builds a cluster, the breathing space keeps reducing, and the perfect dance of spin and immaculate angles in the field triumphed once again.