A quest that began in 2004 will intensify this year as the All Blacks increase their determination to find that elusive player who can genuinely flit between loose forward and lock.
All Blacks coach Steve Hansen has been after someone like this since he was appointed assistant coach 12 years ago but has only ever had fleeting moments of success.
Former Auckland and Blues player Angus Macdonald was one of the first who looked like he might fit the bill. Capped on the end-of-year tour in 2005, he didn't push on and was never seen again.
The next two projects were Troy Flavell and Reuben Thorne in 2006 and 2007 respectively. Flavell was the great hope, being 1.98m and 118kg, but couldn't offer the consistency of performance they were after.
It was Thorne in the end who went to the 2007 World Cup in that dual capacity but he really didn't have the height or bulk to get away with playing lock at that level.
Previous failures haven't deterred Hansen and his desire for this project is undiminished.
In fact, it has greatly increased in the wake of a World Cup campaign that saw the All Blacks successfully buck convention and not select a specialist lock on their bench.
When the idea of picking two loose forwards on the bench rather than the customary one with a specialist lock was first seriously aired ahead of the World Cup squad being finalised, it sounded like the sort of risk that would be too great to ever take.
But satisfied the reward would outweigh the risk, Hansen experimented in the early rounds of the tournament and saw enough to be convinced the idea had value.
What persuaded him was partly the confidence he had in the likes of Jerome Kaino, Victor Vito and Kieran Read to fill in at lock if they had to.
The other factor driving this change was the evolving nature of test football. The key battle ground has shifted from the scrum to the tackled ball and the All Blacks, eager to play with pace and width through 80 minutes, felt they would be better served injecting two fresh loose forwards off the bench.
There are obvious rewards linked to having four loose forwards on the field in the final quarter: more presence at the tackled ball, quicker support to line breaks and more ball carriers and agile tacklers.
The risk, of course, is that the scrum is greatly weakened, the lineout can be compromised and there is increased vulnerability to the rolling maul.
The deeper risk for the All Blacks would be an early injury to either Sam Whitelock or Brodie Retallick. Kaino, Vito and Read could scramble through 25-30 minutes if they had to but, if that was pushed out to 65-70 minutes, they could struggle.
The bit that taxes them is scrummaging - the weight and power that comes through the middle of the scrum is on a different spectrum. If one of the locks isn't doing his bit, everyone knows. It basically kills the legs and then much of the rationale for having a loose forward at lock is made redundant because the player in question can't get around the field.
The best way for the All Blacks to mitigate those risks is to find a player who is good enough to be considered a test-quality lock and test-quality loose forward.
That special hybrid hasn't ever quite been found - it's a near impossible brief because the mix of attributes needed to excel at lock are on the cusp of conflicting with those required to be a test loose forward.
Mobility and agility are key to playing in the back-row, as is having the frame and elasticity to be able to stay strong over the tackled ball and compete for it on the ground.
Yet, in contrast, ballast and strength endurance are needed to lock the scrum and height is a necessity at the lineout.
Two men in Super Rugby are providing hope that they could develop into genuine contenders.
One is Blade Thomson at the Hurricanes. He is rangy, dynamic and strong, but hasn't quite convinced Hansen yet he's got what it takes to play test football.
The other hope is Steven Luatua, who has played ample football at lock and was shifted to start there for the Blues on Friday night against the Hurricanes.
He has the mobility and aerial skills with the bigger question being around his scrummaging prowess.
"I think it's an easier transition for Steven because he started off in the engine room and he's good at it," said Blues captain Jerome Kaino of Luatua's switch to lock.
"He's quite strong and also explosive at lineout [time]. For me, when I have to go in there, it's a bit of an adjustment but I don't mind ... although better Steven than me."