All stats exclude the ongoing Lord's Test

Over the last couple of years several batting legends have announced retirements. Sachin Tendulkar, Jacques Kallis, Mahela Jayawardene, Rahul Dravid, Ricky Ponting have all quit the game, Kumar Sangakkara has two more Tests to go, and Kevin Pietersen is no longer in England's plans. Younis Khan and Misbah-ul-Haq are still going strong for Pakistan, but they're the exceptions; mostly, the last couple of years have been about a change of batting guard.

With the previous generation making way, there have been opportunities for the next generation to make a mark, and over the last couple of years some have done that more convincingly than others. More than the others, four young batsmen have shown special skills in their brief careers - and especially over the last couple of years - suggesting that they could be the batting stars for the next several seasons. Three of them have been in action during the English summer, while the fourth played there last year - with little success - but has scored runs everywhere else.

Steven Smith, Joe Root, Kane Williamson, and Virat Kohli. Each of them is in the top ten in the ICC Test rankings for batsmen, and have remarkably similar numbers, especially in the last couple of years. In terms of career averages Root leads the way but there's little to choose between him and Smith - both average in the mid-50s - while Williamson and Kohli are similarly bunched together in the mid-40s. In terms of age, though, Root and Williamson are bunched together - both will turn 25 later this year - while Smith and Kohli are both 26 already.

It's in the last two-and-a-half years, however, that all four have really come into their own as Test batsmen. Williamson and Smith made their Test debuts in 2010 - before the other two - but Williamson only averaged 32.71 in his first 18 Tests, before 2013, while Smith played five Tests before 2013 and averaged less than 30. Similarly, Kohli, before 2013, played 14 Tests and averaged fractionally under 39.

Since the start of 2013, they all average more than 50. Smith leads with a 60-plus average, Root and Williamson are in the mid-50s, and Kohli just touches 50. They all have excellent conversion rates of getting hundreds, and have become the lynchpins of their teams' batting line-ups.

A further break-up of home and away numbers indicate that all four have better stats at home, which isn't a surprise, but Kohli and Williamson have plenty of centuries in away Tests, while Smith and Root have scored most of theirs at home. For Root, six of his seven centuries have been at home - the only away ton was his unbeaten 182 in the West Indies earlier this year. In seven Tests in Australia and New Zealand, he averages only 23.33, with one half-century in 13 innings. He has played only one Test in Asia, and none at all in South Africa, so those are challenges that await as well.

Smith's stats are more even. He had an exceptional series in South Africa last year, scoring 269 runs in three Tests, while he has also had a decent time in Asia, averaging almost 42 in eight innings. Smith's problem has been England - he averages just 34 in eight Tests there - but he has an opportunity to rectify those numbers over the next few weeks.

For Kohli too, England has been the one stumbling block - he has centuries in Australia (five of them), South Africa and New Zealand, but in ten innings in England last year, he aggregated only 134. However, in 24 innings in Australia, South Africa and New Zealand, his average is an exceptional 64.26, with seven centuries in 12 Tests.

Williamson, on the other hand, seems to prefer spin to pace, despite playing most of his cricket in seamer-friendly conditions. His home average is an impressive 57, but in England, Australia and South Africa, his average drops to 22.62 from 16 innings, with only two fifty-plus scores. His only century in these conditions came earlier this year, when he scored 132 at Lord's. In Asia, though, his average goes up to 47.61 from 21 innings, with a hundred each in India, Sri Lanka, the UAE and Bangladesh.

It needs to be stressed, however, that these are early days for all these batsmen, and they'll surely get plenty of opportunities to fill these gaps.

The pace-spin numbers for the four batsmen are similar too, with all of them doing better against spin. Kohli's average against pace is the lowest among the four - marginally below Williamson's - largely because of his poor series in England: James Anderson has had his number, dismissing him five times in Tests at an average of 8.40 runs per wicket. However, Kohli has pretty good numbers against some of the other top quick bowlers around - he has stats of three dismissals for 146 runs against Mitchell Johnson, 2 for 133 against Ryan Harris, 1 for 112 against Mitchell Starc, 2 for 93 versus Tim Southee, 0 for 85 against Trent Boult, and 1 for 48 against Dale Steyn.

The bowler who has dismissed Williamson most often in Tests isn't a quick bowler but India's left-arm spinner Pragyan Ojha, who has figures of 5 for 91 against him. Among the fast bowlers who've troubled him the most are Anderson (4 for 103), Kemar Roach (4 for 104), Steyn (3 for 37) and Vernon Philander (3 for 44). If the Ojha numbers suggest a weakness against left-arm spin, then there's a strong counter to that argument in his stats against Rangana Herath - one dismissal for 144 runs, off 302 balls.

Smith's least favourite bowlers - going by stats - are Chris Tremlett (4 for 70) and Stuart Broad (4 for 95), while against Anderson the numbers are pretty even - 5 for 202 (before the Lord's Test). He has done even better against Philander (0 for 82), Mohammed Shami (1 for 112) and R Ashwin (1 for 216). He has faced only 62 balls from Steyn (1 for 27), but they'll probably have a few more battles before Steyn retires.

Root would have probably been the most relieved to hear about Harris' retirement before the start of the Ashes series - he has stats of 5 for 72 against him, an average of 14.40. The other two bowlers who've really troubled him are also those who bowl a fairly full length and move the ball - against Tim Southee he has stats of 4 for 99, and against Trent Boult 3 for 83. However, he has done better against Johnson (2 for 109) and Starc (2 for 85). Root's numbers against spin are the best among the four, but then he has played only one Test in Asia.

Over the next few years, all these batsmen will face varied bowling attacks, in different conditions. If their careers pan out according to expectations, they could well be the next batting legends, and worthy successors to the likes of Tendulkar, Kallis and Ponting.