Imagine there was no Kane Williamson. It's not easy, don't try

In a parallel universe Kane Williamson never seriously takes up cricket. It is only one of several sports he tries, as is ordinary for a kid growing up in sleepy coastal Tauranga.

In this universe, he doesn't work at his batting long enough to show precocious talent. He and his father, Brett, do not spend countless hours in the nets near his house putting the building blocks of a compact and effortless technique together. He doesn't glide into age-group teams as the youngest player by several years. Doesn't find himself in senior sides at the age of 16. Doesn't have stellar first-class seasons late in his teens. There's no debut for New Zealand two days after turning 20.

Here, the various spots Williamson occupies in first-class sides, and eventually the national team, are taken up by your run-of-the-mill New Zealand domestic performers at the time. We could take names, but if you followed New Zealand through this spell you'd only be too familiar with the type. They can survive some swing and are okay on the front foot for a while.

But bouncers with a bit of heat? No thanks, we don't like that stuff here.

Big-turning spin? Uh, sorry, what now?

These batters will look good for a 30 here, scratch out a 40 there, get out in single figures too often, and eventually be jettisoned for the next player on a domestic hot streak, who brings roughly the same skill set to the park. We'll call this genre of batters NotWilliamson.

Perhaps the real Williamson is off at university, studying computer science or marketing. He's not around in Hobart in 2011 to hit an important 34 off 48. On a rampantly grassy track, Ross Taylor needed his partner to take the heat off him while he batted for 169 balls to put together a 56 that was the centrepiece of New Zealand's second innings.

In our universe New Zealand went on to sneak a famous seven-run win, which was the single flowering tree in the otherwise drought-ridden nightmarescape of their Test fortunes at the time. Would NotWilliamson have been capable of that vital cameo late on day two? Not likely.

That home summer, Williamson is not there to produce his first great act of defiance. South Africa are in the middle of their rampaging away streak - Dale Steyn slinging meteors, early-career Vernon Philander swallowing top orders whole, Morne Morkel raining down skyscraper bounce. New Zealand must bat out more than 80 overs on the final day at the Basin Reserve to avoid a 2-0 series defeat. But NotWilliamson does not have the technique to survive the storm of bouncers, is not wired to let South Africa's verbal daggers fly harmlessly by, does not have the youthful spunk to blow bubblegum bubbles as he puts away the occasional bad ball, is incapable of hitting a 228-ball, match-saving 102 not out.

You see where this is going, right?

Later in 2012, New Zealand are in Sri Lanka, having bombed in five Tests on the bounce. Taylor has been told he is being dumped as captain, and sets his will on proving a point. But at the P Sara Oval he doesn't have Williamson to forge a 262-run stand with - a partnership that would become the foundation of a win that preserves a sliver of his dignity.

Between 2013 and the end of 2015, when new captain, Brendon McCullum, and coach, Mike Hesson, set the team off on an inspired new direction, it is beyond them to conjure up a batter who would hit ten Test hundreds and average 61.91 through the period, nor one who personifies their new team ethos before they'd ever conceived of it.

Williamson is not so much a "nice guy" as a guy to whom it would not occur to be anything other than he is, which is nice. New Zealand, now desperate to fight perceptions they are prima donnas, want to be restrained in victory and defeat. Williamson doesn't so much have a poker face so much as a poker personality.

There are the more tangible things. The McCullum and Hesson of the parallel universe also don't have Williamson's 113 in a Test against India in Auckland (which in our universe New Zealand win by 40 runs). They don't have the second-innings 161 not out that would set up a 53-run victory in Bridgetown.

In Sharjah they don't have the 192 off 244 that helps set up a victory they may not get to without that contribution. At the Basin Reserve they absolutely would lose to Sri Lanka without Williamson's game-breaking 242 not out, and at the Gabba later in 2015 they do not have Williamson making 140 and 59 and Australians sitting back and remarking, "Uff, this is a serious player."

You begin to wonder what shape New Zealand's cricket takes in this alternative reality. You question how high they would really rise through the course of the 2010s.

Tim Southee and Trent Boult still swing the new ball deliciously, but without the runs Williamson produces at a rate that far outstrips any New Zealand batter before, how often do they take matches deep? Neil Wagner has become the second-innings sledgehammer that breaks batting orders open as New Zealand pursue wins. Minus Williamson's runs, how much road does he have on which to make his furious charges?

And without the roaring success of McCullum's proto-Bazball as captain of the New Zealand team, does Bazball^TM ever seriously see the light of day? McCullum was such an exhilarating presence in the dressing room, his players "willing to run through a wall for him", as one put it. This is fine, but broken walls don't tend to help teams win matches. Runs, though…

Runs, by the way, that come relentlessly, save for when New Zealand's Test schedule dries up for months at a time, as it does repeatedly during Williamson's career. On his own account there are no extended dips in form, no long injury layoffs. There is his 53 and 104 not out after Bangladesh pile on 595 for 8 at the Basin, 89 and 139 to clinch the series against Pakistan in Abu Dhabi, the match high-score of 89 on a wildly seaming pitch against Jasprit Bumrah and Co, a glorious 132 following-on to set up that incredible one-run win against England, and the small matter of him scoring more than any other batter in the World Test Championship final he led his team to victory in.

Cast a close eye over this career and quickly it becomes clear that the leading predictor of New Zealand's chances of victory in Tests is whether Williamson prospers. It becomes difficult to avoid the conclusion that while McCullum, Taylor, Southee, Boult and Wagner have all played major roles in their team's transformation into their country's greatest ever team, it is Williamson who has most bent New Zealand's arc towards excellence. In wins, he averages 81.61. No other batter has contributed anywhere near as many runs to New Zealand victories, nor done it at close to this average.

In fact, only Don Bradman in the history of Test cricket has ever been better in victories. Among his contemporaries (as the subject is Williamson, you could never call them rivals) Steve Smith averages 67.93 in wins, Joe Root is about six runs behind Smith, and Babar Azam and Virat Kohli are lower down still. In temperament Williamson sets himself apart further. Where the others have developed on-field affectations - Smith's quirks, for example, or Kohli's intensity - to transport minds and bodily molecules into the reaches of greatness, Williamson tends to bat like it is as plain a thing to him as breathing. A glide back into the crease, a drifting up on to tiptoes, a serene push into space in the covers.

Even in the earliest days of his career, he was expected to become his nation's greatest ever batter. Smith, Root, Kohli and Babar Azam have all had their travails; public interrogations, tears, outbursts, oustings, recriminations. Williamson has floated to 100 Tests as if carried on a breeze.

Along the way he has surpassed even those early predictions. He is so peerless as a New Zealand batter, the only conversation now is whether he or Richard Hadlee is their greatest cricketer. Hadlee still wins, perhaps, because he was even more peerless, and excelled in a team less studded with other greats. But the New Zealand of the 1980s also never scaled the peaks New Zealand of the last 12 years have planted their flag upon.

Maybe in the parallel universe a 33-year-old Williamson is managing a software- solutions outfit. Or totting up whale numbers in the southern Tasman Sea as a marine biologist. Such is the quiet joy he takes in all the little things - the running off the field to taste a birthday cake spectators have produced for him during a practice match near Colombo, or joking with journalists ahead of a press conference prior to a big game - you suspect he would be as fulfilled in any of those careers as he has been piling up runs.

The New Zealand team, though, would not have charted their route to such glory. In fact, it is possible they would have been a shadow.

Cricket has been lucky to have him in our reality.