If you fed a selection of R Ashwin's bowling statistics to a clustering algorithm, chances are that he would be grouped with fast bowlers rather than spinners. Over the years, Ashwin's numbers in Test cricket have taken a shape that fast bowlers would envy. A career strike rate of 53 puts him between Brett Lee and Morne Morkel among bowlers to take at least 300 wickets in Tests. Out of the 35 bowlers to have taken 300 or more wickets, 24 have an inferior strike rate than Ashwin and 16 of them are fast bowlers. No spinner has a better strike rate than he has. Muttiah Muralitharan comes the closest with a strike rate of 55.0.

The race to 400 wickets
Ashwin has taken 21,242 balls to take 400 wickets, which makes him the fourth-quickest bowler ever to the landmark. Only Dale Steyn, Richard Hadlee and Glenn McGrath have got to 400 wickets in fewer deliveries. Rangana Herath is the quickest spinner after Ashwin, having taken 23,835 deliveries.

In terms of matches taken to take 400 wickets, only Muralitharan was faster than Ashwin because of having averaged higher number of balls per match than Ashwin. Ashwin has reached the milestone in his 77th match, which is three matches fewer than the next quickest bowler among the 15 bowlers who completed 400 wickets before him.

Ashwin is also the second-quickest in terms of time taken from making his debut, having reached the milestone in 9 years and 110 days since making his debut (days to the start of the match in which the milestone was reached). McGrath took just 8 years and 341 days, and is the quickest among all bowlers.

The new-ball specialist
Ashwin's effectiveness with the new ball makes him a unique spinner whose utility transcends the limit imposed by the skills of a spinner. He has some nifty tricks up his sleeve, not the least impressive of which is the drift he is able to get with the new ball with the seam upright that - but for the lack of pace - mimics the inswinger bowled by a fast bowler to right-hand batsman. Coupled with intelligent use of the crease, Ashwin is adept at beating both the edges of the bat.

With variations like these in his armoury, Ashwin has taken 59 wickets in the first 15 overs of the innings in Tests at a strike rate of 47.4. Among ten bowlers to take at least 50 wickets in the first 15 overs since his debut, Ashwin is the only one with a strike rate under 50. Steyn just misses the cut-off in the period since Ashwin's debut. But even Steyn - admittedly on the decline in the latter half of this period - took 53.2 balls on an average to take a wicket.

Ashwin hasn't been effective with the new ball only in the second innings when the pitches would've deteriorated so much that spinners were into play early. He has taken 25 wickets at a staggering average of 16.04 and a strike rate of 41.1 in the first innings as well. No other bowler - pacers included - has taken 20 or more wickets at a better strike rate than Ashwin. Kemar Roach is the next best bowler having taken 35 wickets at a strike rate of 45.9 in the first fifteen overs.

Ashwin is the highest wicket-taker for India in the first 15 overs of the innings since his debut. Ishant Sharma, who has taken 50 wickets with the new ball is the next prolific bowler for India in this period. Among spinners, Herath is next with 45 wickets.

India's de-facto spearhead
Since Ashwin made his debut, India's bowlers have taken 1312 wickets in Test cricket in matches he played. Ashwin has contributed 30.5% of those wickets, which is the fourth highest among 35 bowlers who've taken at least 300 wickets in their career. For India, only Anil Kumble has contributed more wickets, but only by a fraction more. Kumble took 30.7% of wickets by India's bowlers in Tests in which he played.

In fact, before 2018, when India's fast bowling riches materialized at the Test level, Ashwin had contributed nearly a third of India's wickets (32.9). That was the third highest ever among bowlers with 300 or more wickets till that time, next only to Muralitharan (40.4) and Hadlee (35.7).

Scourge of left handers
Ashwin's excellent record against left-hand batsmen is well known. No one in the history of Test cricket has dismissed most left-hand batsmen. However, if you think that Ashwin has dismissed as many left-handers just because there are more of them in Test cricket now than ever, then consider the following.

There have been 601 innings - till the time Ashwin took his 400th wicket - by left-handers in the matches when Ashwin has played. The 204 dismissals he has inflicted makes that a percentage of 33.94. Among bowlers with at least 200 wickets in Tests, only Alec Bedser has ended a higher percentage of left-handed batsmen's innings. In the last fifty years, only Muralitharan comes close to Ashwin, having ended 191 of 624 innings by left-handers.

Towering overs others at home
With 278 wickets at an average of 22.19, and a five-wicket haul in every other match in Tests in India he is a champion bowler at home. But helpful conditions don't guarantee wickets by default. The best bowlers make use of the conditions to the fullest, which Ashwin has done well over his career. In matches Ashwin has played at home, the other bowlers have averaged 34.1. The difference of 11.9 between Ashwin's average and the match average of other bowlers is the third highest for any bowler to have taken at least 200 wickets playing at home. Only Muralitharan and McGrath have out-bowled other bowlers by a bigger extent.

Moreover, Ashwin has built this gap between him and others largely in the presence of Ravindra Jadeja, who himself has excellent numbers in India (Jadeja averages 21.06 in Tests in India).

Improving performance in SENA countries
Ashwin's indifferent numbers in the SENA countries (South Africa, England, New Zealand and Australia) do take some sheen off a record that otherwise would place him among the pantheon of all-time great bowlers. He has taken 63 wickets at an average of 40.11 in Tests in these four countries, which pales in comparison to his record elsewhere. He concedes nearly 15 runs more on an average to prise out a wicket in these countries when compared with his overall career. Among India spinners to take at least 20 wickets in these countries, only S Venkataraghavan and Venkatapathy Raju have a higher average than Ashwin.

However, these countries are tough for all spinners, not just Ashwin: none of the active spinners average sub-30 bowling in Tests in the SENA countries. Among them is Yasir Shah, who has struggled in these conditions: his 46 wickets have come at 55.08 apiece.

Any spinner worth the name from India can't escape comparisons to the likes of Bishan Bedi, Bhagwat Chandrasekhar and Erapalli Prasanna. Bedi took 90 wickets in England, Australia and New Zealand at an average of 30.98. Prasanna's 78 wickets came at 29.94 apiece and Chandrasekhar, whose average is closest among the three to Ashwin's but still a good nine runs better, took 71 wickets at 31.33. Chandrasekhar took six five-wicket hauls in 19 matches in the SENA countries, while Ashwin is yet to take one from 20 Tests.

However, to be fair to Ashwin, he hasn't bowled as much on tours to these countries. He has been on nine tours but has played just 20 Tests - an average of 2.2 matches worth of bowling per tour. In comparison, Prasanna averaged 3.3 matches per tour, Bedi 3.1, and Chandrasekhar 2.7 matches per tour. This discounts the bowling time they would've got in the tour matches, which players don't get in these times of packed cricket calendars.

Ashwin has shown that this effectiveness in conditions increases with his experience of bowling in them. It was on evidence in the first Test of India's England tour in 2018, when he took seven wickets at an average 17.28. He had gained invaluable experience bowling for Worcestershire in the county the previous year.

Ashwin's ability to adapt is clearer when we look at his performances in Australia over the years. He has been on four tours to Australia and on evidence from the last tour, has worked out how to deceive batsmen without help from the pitch. He's played three Tests on three of the four tours. On the first tour in 2011-12, he took nine wickets at an average of 62.77; he improved to 12 wickets at 48.66 on his next tour in 2014-15. On his last tour, Ashwin out-bowled Nathan Lyon - bettering the Australian bowler at the skill of getting overspin and use of the crease on Australian pitches, taking 12 wickets at an average of 28.83. This was against a full-strength Australian batting line-up, in condition that weren't particularly helpful to spinners.

Not too long ago Ashwin wasn't the first choice spinner when India played outside the subcontinent. Ashwin's recent track record in Tests has shown he's coming up with ways to take the pitch out of the equation, and could well prove to be the bowler India would turn to in all conditions.

Shiva Jayaraman is a senior stats analyst at ESPNcricinfo @shiva_cricinfo