There's a mystique and reverence that comes with playing fly-half in rugby union with the individual in the No.10 jersey capable of deciding a game.
That ability to make-or-break a match has helped to create many a legend of the sport, none greater than All Blacks hero Dan Carter, who turns 40 today (5th March).
The two-time Rugby World Cup winner hung up his boots in February 2021, calling time on one of the greatest individual careers the sport has ever seen.
As Carter celebrates entering his 40s, now is a good time to remind ourselves just how good the 'Perfect 10' was, and who stands behind him in the fly-half hall of fame.
Few could have predicted the impact Carter would have as a fly-half when he broke onto the international rugby scene as an inside centre in 2003, although there were hints to his future greatness when he notched 20 points on his debut in New Zealand's 55-3 demolition of Wales.
He would quickly establish himself as a regular in the All Blacks side and once he got hold of the No.10 shirt only injury was able to rip it from his grasp as he kept Nick Evans and Aaron Cruden on the sidelines.
Those two would have walked into any other side but Carter's all-round game was too good to even consider dropping him when fit. Not only was he deadly accurate with the boot, his time at centre helped him develop an excellent running game and strong defence. His ability to read the game was second to none and he rarely looked flustered, proving himself to be a true Test match animal.
When he eventually called time on his 112-cap international career after a man of the match performance in the 2015 Rugby World Cup final, there could be no doubts who the greatest fly-half of them all was.
The three-time World Rugby Player of the Year is Test rugby's all-time leading point scorer with 1598 points to his name, the last of which came with a wrong foot conversion in the World Cup final.
Carter won 99 of his 112 games for New Zealand and would have easily gone past a century of victories had injuries not slowed him down.
The nature of rugby means injuries are part and parcel of the sport with every player - even those not in the trenches, like fly-halves - having their stories to tell.
Carter missed game time at two consecutive World Cups as a result of injuries but his health issues can't quite match those suffered by arguably rugby's second greatest No.10, Jonny Wilkinson.
Second on Test rugby's all-time points list with 1,246 points, Wilkinson and Carter were for a time engaged in their own personal dual to lead the standings before the Englishman dropped out of the race when retiring from the international game in 2011 having won 91 caps.
A lack of a running game diminishes Wilkinson's standing in the world game to some but he more than made up for that apparent deficiency with his deadly accurate goal kicking and strong defensive game.
Best remembered for slotting the winning dropping goal in England's 2003 Rugby World Cup final win over Australia, Wilkinson nearly booted the Red Rose to back-to-back Webb Ellis trophies in 2007, only to fall agonisingly short in the final.
A four-time Six Nations winner and highly successful talent at club level with Toulon and Newcastle, Wilkinson has certainly earned his spot amongst the sport's greats.
He might not be the greatest fly-half ever to anyone outside of Wales but there's a reason they refer to the Barry John as 'The King' in Cardiff and beyond. Despite only winning 25 for Wales between 1966 and 1972 before early retirement, John left a lasting impression.
His biggest impact arguably came as a British & Irish Lion. He stole the show on the 1971 tour of New Zealand as the Lions came home victorious with John scoring in every game on the tour.
Like John to Wales and Wilkinson to England, most nations have that one great fly-half and for Australia, that man is Michael Lynagh. The Wallabies' all-time leading Test points scorer started out at centre but moved to fly-half when another legendary No.10 Mark Ella called it a day.
Lynagh was vital to Australia's World Cup-winning side of 1991 and retired having won 72 caps and scored 911 points.
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