This is the hand that is redefining the way rugby is played.

It's an otherworldly appendage, gripping an elliptical ball - circumference approximately 600mm - like most hands grip a cheeseburger.

Attached to an arm that has Inspector Gadget-like properties, this hand is wreaking havoc while having fun, flicking the Gilbert this way and that, popping it up, faking passes and generally making life difficult for those in charge of keeping it in check.

We've seen great hands toy with the ball before.

Colin Meads' King Country farm-hardened hands were equally adept at wrapping around the leather ball as they were a tanalised fencepost. His have become mythical hands, but even they would concede they did not have the dexterity and range of tricks as the hand on this page.

Because no single hand has made quite the immediate impact in international rugby as Sonny Bill Williams' right mitt.

If Liberace and Richard Clayderman could insure their piano-playing hands, surely the New Zealand Rugby Union can take out a policy on Williams' prehensiles.

"He's different to anything we've ever seen. It's not a usual rugby union style. It's interesting to people and it's good for our team," said All Black assistant coach Wayne Smith, who hours after uttering this statement sat on a selection panel that decided the good people of Ireland would only get to watch the hand tomorrow if it made an appearance off the bench.

"I haven't seen anyone [like him]," Smith continued. "It's just so different a skill-set to what we've seen before. We've seen the odd guy offload, he does it consistently."

Williams is said to be very personable, very humble in the team environment, as is his hand. While it kindly agreed to have an outline drawn around it, it did not want to be photographed. Which is fine, we live in a country where even the lowliest hands have the right to privacy, though it could open the door for a new generation of hand paparazzo.

At just 25 years old and with few rugby union miles on the clock, this hand will not get any bigger, but it will get smarter. As it's rugby knowledge broadens, it will know instinctively when to hold on to the ball and when to play tricks with it.

And in years to come, those who saw it will tell their grandchildren about the freakiest hand to ever play the sport.

Instinct and vision
Sione Lauaki actually had the ability to make some pretty spectacular one-handed plays, but what he lacked was an inherent game sense. Some people like to call it peripheral vision, others regard it almost like a sixth sense, but early in his rugby career, Williams seems to have developed a freakish awareness of where his support players are and how long it's going to take for them to get there.

It's one thing to have a big paw that can wrap around the ball, it's another to be able to get rid of it accurately and in a number of different ways. If Williams had only one style of offloading, defences would soon learn how and where to attack him in the tackle. But Williams can pop conventional passes out of the front of his hand, he can flick them out reverse, giving the illusion he is passing them out the back of his hand. He can throw overhead passes, quarterback style and, at least once, has thrown something that can only be described as a backhand, overhead throw.

It doesn't matter if you've got the hands the size of dinner plates and eyes in the back of your head, if you're knocked to the ground too easily. Even in contact, Williams is strong enough to stay on his feet for long enough to get his arms free for the pass.

Rugby players grow up with an inherent respect for possession. To lose it means forwards having to graft away at the set-piece and breakdowns to try to receive it. Williams grew up playing league, where the one-handed offload was encouraged asaway of unlocking defences. While it was high-risk, coaches could take the odd mistake here and there knowing that in five tackles' time, the ball would most likely be kicked back to them. "He came through a period, from age 15 to 20, in rugby league where it [the offload] was a big part of the game," Wayne Smith said.

"It's like that book Outliers, there's always coincidences and luck in the development of outstanding traits," said Smith. It's an important point that cannot be overlooked. What if, when Williams was at Mt Albert Grammar,awell-meaning staff member told him professional sport was an unrealistic pursuit and encouraged him to get a trade? What if Williams listened? What if, at his first few months at the Canterbury Bulldogs, the coaches told him to put his "showboating" skills away and concentrate only on his core skills? What if he decided rugby was not for him? There were several points along the journey where Williams' extreme talent could have been derailed. Fans can only be thankful they were not.

It is a big mitt, measuring approximately 190 mms from the tip of the thumb to the tip of his pinkie finger when outstretched. It is about 205mm in length and 100mm in breadth. The average length of an adult male hand is 189mm, while the average breadth is 84mm. It's a simple anatomical fact that the bigger the hands, the easier it is to wrap them around the ball and grip it tight, so it is not as easy to dislodge in contact. Particularly when carrying the ball one-handed.