David Campese had one, and he never tired of telling people about it. John Eales had one too, but was congenitally incapable of boasting. Serge Blanco and Mark Ella were similarly blessed; so was the Welsh outside-half Arwel Thomas, although he never scaled the heights of the others because he was knee-high to a grasshopper, 5st dripping wet and played in an age when behemoths were beginning to roam the rugby earth, eating dimensionally challenged folk like him for breakfast, lunch and dinner.
We are talking of imagination: a gift, bestowed only on the select few, to think and act differently on the field, and by so doing to make rugby new.
If anyone is capable of delivering mind-altering performances in today's Premiership, a tournament generally fought out on the tiniest margins between players who do pretty much the same thing, it is the Saracens hooker Schalk Brits – a front-row forward who, with his startling pace, intricate footwork, slide-rule running angles and exquisite timing (not to mention the precision of his passing off either hand), makes and creates more line-breaks over the long stretch of a season than entire back divisions inhabiting the lower reaches of the league table.
The elfin Thomas would regard him as a kindred spirit, not least because Brits has also fallen victim to the size obsession.
"Rugby is a game of perceptions," he says, tucking into a plate of something indescribable, if undoubtedly healthy, after a training session ahead of this evening's Premiership semi-final with Leicester at Welford Road. "The perception back home in South Africa is that if you don't weigh 110kg minimum, you can't scrummage. And in South Africa, the scrum is a pretty big part of the game. I can argue with that assumption until I'm blue in the face, but I'm not the guy who picks the team. I fought my battle to play rugby the way I want to play it and I'm happy I did so, but I can't force selectors to select me."
Brits has three Springbok caps to his name: in 2008, he came off the bench against Italy and New Zealand before starting a Tri-Nations Test against the Wallabies in Perth. Those who think he should have three dozen shake their heads at the injustice of it all and it was ironic in the extreme that, when another South African hooker materialised at Saracens after last year's World Cup, it turned out to be none other than John Smit, whose vital statistics on both the physical and representational fronts are rather different. Magnificent though Smit has been in leading the Boks through thick and thin, no one ever accused him of artistry. He is, however, three inches taller and more than three stone heavier than his countryman, which may explain why, when it comes to the cap count, he is 108 ahead.
While acknowledging that Smit will take a bit of catching, Brits has not abandoned hope of playing his way back into the thoughts of the Springbok hierarchy. He is committed to spending another season at Saracens, but come the summer of next year he may, depending on the lie of the land in the republic, target a place in the squad for the World Cup in 2015. Already in his early thirties – he turns 31 on Wednesday – he will be no spring chicken by the time that tournament kicks off at Twickenham, but then, Smit was 33 going into last autumn's competition in New Zealand. Age does not wither the best front-row forwards, perhaps because they were withered before they started.
"I knew when I left the Stormers [the Super 15 franchise based in Cape Town] to come to England that my chances of playing international rugby would go downhill," says the man from Empangeni, a small town in the hill country north of Durban on the KwaZulu-Natal coast. "That was a calculation I made, knowing the full implications. Regrets? None at all. I came here to experience rugby of a different kind, in a different place, and it's been amazing. Now that the game is internationalising itself more every year, with players switching hemispheres in ever greater numbers, I'd like to think I'll get another chance. My fondest wish would be to play in the next World Cup against an England team with Jamie George at hooker."
George, a 21-year-old forward from Welwyn Garden City, is one of the brightest prospects in the red-rose game, one of two brilliant young hookers with an eye on Brits' place in the Saracens senior side – the other being Scott Spurling, the current England Under-20 player from central London. Both have been the talk of the coaching community for a while now. Does the South African believe they have what it takes? "Far from being overrated, I think they're underrated," he replies. "Outstanding talents, both of them. I'm not a gambling man, but I have a £100 bet with someone that Jamie will play at the next World Cup." Is he standing in their way, then? "I'd never want to hold them back. I'll do whatever is best for Saracens."
If Brits has bought into the Saracens "project", as it is routinely described, it is not simply because of the South African influence at work there, both at board level and in the playing squad. He thinks, not unreasonably, that the reigning English champions are unique in their approach to team-building, not only in the pure rugby sense but in terms of pastoral care and individual development away from the game.
"Brendan Venter [the World Cup-winning Springbok centre who joined Saracens as director of rugby in 2009 and set about creating a club in his own image] started the process, but it has continued since he returned home," Brits says. "What other club would organise a trip to the Munich Beer Festival for the players and also set up a crèche for your kids? What other club provides the same service for the people in the youth team as they provide for the guys in the Premiership side? I've never seen anything like it in rugby and I'm proud to be a part of it.
"The way I see it, I'm one of the lucky ones. I've been able to make a career in rugby while seeing rugby only as a small part of life. It's never been everything to me: life is about balance, and maintaining that balance allows me to enjoy doing what I do. When I was first making my way in senior rugby, I was also doing a degree in accountancy. That gave me the freedom to give the game a go for a year or so in the knowledge that, if it didn't work out, there was somewhere else to turn. These days, young players turn professional much earlier. It's why the club takes the personal development side of things so seriously."
When Brits talks of freedom, he speaks as he plays: when he has the ball in his hands, a broken field in front of him, he is in his element. Two years ago, he was one of the crucial components in a late-season flowing of attacking rugby that surprised all those who had spent the previous weeks and months watching a risk-free, functional, methodical Saracens eke out victories over opponents who could not find a way of breaking down their structures. Prompted by a small but significant change to the refereeing of the tackle area, there was a sudden change. The spine of the Saracens side – an inventive full-back in Alex Goode, an Indian summer-warmed outside-half in Glen Jackson, a crafty scrum-half in Neil de Kock, a high-class footballing No 8 in Ernst Joubert and Brits – coalesced in a completely fresh approach that damned nearly brought them a first league title.
So what happened? Goode, De Kock, Joubert and Brits are still in place, but the Watford-based club no longer trip the light fantastic. They are still hellishly difficult to beat, but they rarely send the spirit soaring. Brits puts it down to a couple of factors: a subtle difference in the way referees operate in 2012 as opposed to 2010 – he believes it is significantly easier to play a more open running style of rugby in the southern hemisphere under Super 15 law interpretations – allied to the fact that the analysts at rival clubs slowly worked out a way of cramping the style of the new, free-flowing Sarries.
"People learnt how to play against us, how to stop us doing what we were doing," he says. "So what we do now is about discipline and control and structure. It may not be flash, but we're winning games. If you're asking me if I'd prefer to play unstructured rugby, the answer is yes: if I had my way, the ball would never be kicked. But the team is always bigger and more important than the individual and this is a sacrifice I'm prepared to make."
Which is not to say that at some point today, in the molten heat of a semi-final between two clubs who bridle at the very thought of each other, he will not pull a rabbit from his scrum-hat.
Discretion may be the better part of valour, but on balance – and as he says, balance is everything – Brits prefers the "nothing ventured, nothing gained" theory of life.