After being omitted from India's XI in Adelaide in 2014, a dejected R Ashwin expressed his desire to be the best in the world to India's bowling coach, B Arun. In the 13 matches India had played outside of Asia since the winter of 2013, Ashwin had played just five, averaging 54.6 with the ball. Spurred by being dropped, he battled an old flaw in his action in net sessions: his alignment at the crease. His front foot was going across his body while delivering the ball, closing off his hip.

Biomechanics research confirms how vital the hip is to a spinner's efficacy. According to a study of the delivery motions of 36 Test match fingerspinners conducted at Loughborough University in 2019, the orientation of the hip at the time of the front foot landing was shown to be the most important factor in how many revolutions the spinner could impart to the ball. Arun gave a detailed account of how this issue was corrected, opening up Ashwin's hip so he could transfer more energy to his bowling arm, put more revolutions on the ball, and bowl with more control.

This change transformed Ashwin's strategies and results against right-handers. We have ball-tracking data for about 50% of Ashwin's deliveries in Test cricket before 2015, and 77% of his deliveries from 2015 onwards. We can use these samples to study this shift.

The plot below shows the distribution of Ashwin's line measured at the stumps during two segments of his career, until the WTC final of 2021. The distribution shifts noticeably after his change in action: while it was peaking on a middle-and-leg line earlier, 2015 onwards it shifts towards the top of off stump, which is the classical attacking line for an offspin bowler. This change was driven by his new, open-hip action. Because of a better alignment, his arm was less likely to fall off towards the leg stump, which shifted his overall line towards off. This off-stump line brings the outside edge into play, opening up more modes of dismissal than just the lbw, bowled or bat-pad that are in play with the middle-and-leg line.

The results of this change are clear in the numbers: Ashwin's average to right-handers dropped from 39.7 before 2015 to 27.1 afterwards. Threatening the off stump also changed the distribution of his wicket-taking modes. Before 2015, 47% of his right-hander dismissals were caught, 23.5% were bowled and 27% were lbw. After the change in action, 60.9% of his right-hander wickets have been caught, 22.5% bowled, and only 14.5% are lbw.

Shifting to a line outside the off stump gives an offbreak bowler greater chances of inviting the drive or of making the batter fend slightly away from the body, which results in greater chances of slip- and bat-pad catches. This line also exposes the stumps more often, leading to a higher chance of getting a batter bowled. Before 2015, Ashwin got a right-hand batter bowled every 316 balls; from 2015 onwards, this happened every 241 balls.

Against left-hand batters, Ashwin possesses an exceptional record, even for an offspin bowler. Fifty one percent of his career wickets have been left-hand bats, at a strike rate of 45.8, which is the lowest among offspin bowlers to have bowled more than 100 balls to left-handers since 2005 (from which time ball-by-ball data is available). Forty-four per cent of Ashwin's career deliveries have been to left-hand batters, the highest among offspinners in the ball-by-ball database.

What makes Ashwin exceptional, compared to the average offspinner, to left-handers?

Overall, Ashwin's strike rate to left-handers is 45% better than that of the average offspinner in the ball-by-ball database. We can break this down by mode of dismissal: his likelihood of getting a left-hand bat out lbw is 37% better than the average, while his rate of getting left-hand players out bowled is a whopping 92% higher than other offspin bowlers. The key to uncovering the reasons for these numbers lies in the areas Ashwin bowls.

The plot below shows distributions of the line of the ball in the plane of the stumps for Ashwin and other offspin bowlers to left-handed batters. Ashwin is much likelier to have the ball end in line with the stumps compared to other offspinners: 52% of his recorded balls end up within the stumps, compared to 36% for other spinners. This translates to a twofold risk: batters are likelier to get bowled or lbw, and likelier to play at deliveries. And if the ball turns to beat the outside edge, there is a higher risk of getting bowled.

Ashwin is not only bowling straighter now but is also deadlier. The plot below shows the bowling strikes rates of Ashwin and other offspinners to left-hand batters, segmented by the line and length of pitching. Only regions with more than 20 balls in them are shown. The values in the cells show the strike rate, and the numbers in brackets for Ashwin are the total balls recorded pitching in that zone.

Ashwin generally has a better strike rate in almost every slot, but the difference for full-length balls (three to five metres from the stumps) on both off and leg stumps is stark. Ashwin is much more successful at outdoing the batter on a fuller length compared to other offspinners, who often get defended on the front foot or driven off similar balls. Ashwin bowls more on turning pitches, but the key to this higher efficacy also lies in his mastery over changes of pace, changes in turn, and what the ball does in the air.

Spinners usually bowl with the seam oriented in one direction. This orientation of the seam not only determines turn off the pitch but also the drift and dip the ball gets. Drift and dip are complementary shades of the same force, and changing the direction of the seam controls the relative amounts of each.

Ostensibly, spin bowling is about the changing line of the ball on pitching. The key to playing spin, however, is gauging length effectively. Playing spin well demands a binary strategy: either going fully forward and meeting the ball right after pitching, or rocking back, letting the ball turn and then playing it. The former minimises the lateral deviation of the ball by having the batter intercept it early, giving the best chance at middling it. The latter gives the batter enough time to watch the ball after turning. In between these two lies the danger of getting out - defending the ball while not reaching the pitch leaves the batter vulnerable to the uncertainty of the turning ball, raising the chances of missing it.

The statistics support this definition of a "danger zone". In Hitting Against The Spin, a book that describes the mechanics of the game through numbers, Nathan Leamon and Ben Jones use ball-tracking and shot-interception data to conclude about playing spin: "…it is far safer to play the ball within 1.5 metres of where it pitches, or to play it over 3.5 metres away from that point. Those areas both average over 80 for top-order players, whereas the most dangerous zone between 2 and 3 metres has an average of just 14."

Because spinners bowl slower than other bowlers, it is easier for batters to adjust to length. The key to deceiving a batter, then, is hoodwinking them over where the ball will pitch.

Here is where dip comes in. The batter estimates the pitching length from the height of the ball and extends their foot forward. A ball with dip drops at the very end of its trajectory, falling shorter than anticipated, in the danger zone.

Ashwin uses this dip expertly to beat the bat in two major modes of dismissal. The right-hand batter's inside edge is threatened by the dipping ball that lands a little farther from the bat than expected, increasing chances of the bat-pad dismissal. A recent instance of this was Steve Smith's dismissal in the second innings of the Melbourne Test of 2020. Smith extended his front foot to reach the pitch, but the ball dipped and deviated more than he had predicted, making him close the bat face and edge it to leg slip.

Another telling example was the wicket of Jermaine Blackwood in the Jamaica Test of 2016. ESPNcricinfo commentary describes the bat-pad catch: "…the ball dips to create a gap between the bat and the pitch of the ball, it then turns to take the inside edge of the bat onto the pad…"

The data supports Ashwin's use of drift to target the inside edge of right-hand batters. The CricViz database records which edge is touched when a batter makes contact with the ball. In Asia, where we have a decent sample size, 39% of other offspinners' wickets come off the inside edge. The corresponding figure is 51.2% for Ashwin, from a total of 39 recorded wickets.

The second form of dismissal is the classical one for an offspin bowler - opening up the batter for the big drive on the off side and sneaking through to hit the stumps. The dismissal of Roston Chase in Rajkot in 2018 illustrates the role of dip beautifully for this case. The ball is floated up, invites a drive, and dips at the very last moment, missing the bat and turning big to hit the stumps.

To left-handers, Ashwin uses dip to threaten the stumps beyond the outside edge off fuller lengths. There are seven bowled dismissals of left-handers in the ball-tracking data for which the pitching line is within the stumps and the length is less than five metres from the stumps. The ESPNcricinfo commentary for six of these mentions either drift or dip. This is what lowers Ashwin's strike rate in the full-length region for balls pitching on middle and leg to left-hand batters (as the strike-rate plot above shows). A classic example of this was his dismissal of Alastair Cook in the Edgbaston Test of 2018. Anticipating a full ball, Cook extends his foot forward gently. The ball dips at the very last moment, landing far ahead of Cook's pushed-out pad, turning past the blade and hitting the stumps. Talking to the host broadcaster later, Ashwin confirmed the role of dip.

Dip, although essential, is not the only component of a spinner's threat. In the example of the Cook wicket, the seam is tilted towards second slip. This generates both dip and drift.

Drift makes the ball deviate laterally mid-air, deceiving the batter into playing down the wrong line. An offspinner's ball drifts towards the leg stump of the left-hander in this instance, making them play straighter. In the Cook dismissal, the ball drifts in gently with the angle, and Cook's push is towards long-on, his chest opened up completely, his off stump exposed.

Drift sets the stage for the batter to miss the away-turning ball. Ben Duckett's wicket in the Vizag Test of 2016 is similar; he is even more squared up by the drift, his front pad moves almost outside leg stump as the ball hits the stumps.

Against the right-hand batter, this outward drift invites the big drive, exposing the bat-pad gap, like in the Chase dismissal above. Less conventionally, Ashwin combines it with pinpoint control over the turn he gets to deftly threaten the outside edge of the bat, making the ball drift away and then skid on with the line. The twin dismissals of Ollie Pope in Ahmedabad earlier this year are classic examples - the ball drifts away and beats the outside edge of the right-hand bat, landing on the leather because Ashwin has released it with his palm facing upwards. The same mechanics were at work when Steve Smith was caught at first slip in Adelaide in 2020.

A more recent example is the wicket of Tom Latham in the second innings of the WTC final. In the 20 balls Ashwin bowled to Latham before getting him out, only two were slower than 85kph, mostly hovering in the late 80s and early 90s. The wicket ball was floated up wide and slow - at 83kph - inviting the drive and creating a catch.

The available tracking data does not have information on release points, so turn can be hard to measure, but we can use it to judge how Ashwin compares with other prominent spinners of today in how he uses variations in pace to get wickets. We will consider all of Ashwin's wickets for which we have tracking data, and for which the previous ball was faced by the same batter. We will then calculate the difference in speed between the wicket-taking ball and the one before it. Although this does not account for longer drawn-out set-ups, it does give us a simple measure of the variation of speed immediately prior to the dismissal.

The table below shows a summary of this "speed variation" for seven spinners for whom a large enough sample is available. The third column shows the proportion of instances in which the speed variation between the wicket ball and the one before it was more than 5kph.

Ashwin employs this variation of speed for more than a third of his wickets (36.59%). Ravindra Jadeja, who is a phenomenal spinner himself, is the only one who comes close. The fourth column shows the proportion of wickets when the speed variation is extreme: more than 10kph. Here too, Ashwin (and Jadeja) are comfortably clear of the others. Ashwin's median variation in speed is also much higher than the other five bowlers in the list.

As Ashwin took bagfuls of wickets at home, discussions of his place among the pantheon of greats always came with the riders of not having done well in the SENA countries - supposedly similar conditions that are different from his home surfaces. In recent years, pitches in England and South Africa have been exceptionally pace-friendly, and Australian pitches have never been known to be kind to fingerspin. Despite all this, considering the period from 2015 to the end of the WTC final, Ashwin has the best average in the SENA nations for specialist spinners who have bowled in ten or more innings and 100 or more overs. He also has the best economy rate (2.62), which points to him being a controller of runs at one end in support of India's recently raring pace battery. In addition, he also has the second-highest wickets-per-innings figure (2.0). The label of Ashwin not being good in these select nations is a misconception that has stuck around for too long - and the record needs to be set right. Ashwin has been the best a spinner can be in the conditions given to him, in addition to being unbelievably good in Asia.

On his YouTube talk show, Murali Kartik asked Ashwin what had changed after that disappointing Australia tour in 2014-15. Ashwin talked about his inexperience, the "exuberance of youth", and about how he looked at the result and not the process. He went on to gorge on footage of great offspinners and videos detailing the execution of various kinds of deliveries, to "learn something from somewhere, and identify and piece together the puzzle" for himself. Ashwin explained that he was a completely different bowler - he was in a better state to control the properties of his deliveries as he wanted because he understood the how of his bowling.

The result of this obsessive devotion to understanding and honing the mechanics of his bowling has been the elevation of Ashwin to No. 2 in the ICC rankings for Test bowlers. Today he is at the peak of the long-form bowler's craft: that holy confluence of cricketing nous to construct wickets and physical ability to execute those plans near perfectly. He already knew how to use the pitch; he has now mastered the art of beating the bat in the air as well. The best in the world.