Conrad Smith is in danger of becoming the king without a heir.
Potential successors have come and gone, flattered and deceived, switched positions, or simply failed to nail one of the toughest jobs in rugby.
But why? And is there anyone capable of doing the All Blacks' No 13 jersey justice when Smith hangs up his boots?
Smith has a theory on the former. He's puzzled over it for years, unsure how he's kept his place in the face of a landslide of talented rivals.
Since his test debut against Italy in 2004, Ma'a Nonu, Isaia Toeava, Anthony Tuitavake, Luke McAlister, Nathan Mauger, Mils Muliaina and Richard Kahui are among the cast to have had a crack in the middle of the backline.
"You get a lot of guys who look, really good at centre in New Zealand," Smith said.
"They will burst on to the scene and even when I started playing it seemed like every year there was another emerging centre but they tended to drop off.
"Everyone asks me what the skill set is for a centre and the thing is I don't think there is one specific skill.
"I've always found it's a position where you have to really adjust to the second five-eighth you are playing with and the rest of the backline really, the wings, the fullback. It's only when you are more experienced that you can do that. You sort of have to understand what the second five-eighth does.
"And it is an understanding.
"People talk a lot about communication in rugby but you often don't have time to call things. It's instinctive and with experience those instincts become something can really trust."
Which leads to another intriguing trend when it comes to All Blacks' centres.
Age. Time. Experience.
Since Joe Stanley made the job his own, it's been older men who have nailed the No 13's role.
Richie McCaw writes in his autobiography: "One lesson from history that we ought to always keep in mind is that the best All Black teams have very experienced specialists at centre.
"Crusties like Joe Stanley and Frank Bunce and Tana Umaga had hard-headed attitudes and considerable age in common: all of them played great rugby into their early thirties."
In fact, aside from Craig Innes, who cut his All Blacks career short at 22, the men who have played centre since Stanley all fit that bill.
Bunce was an instant test hit after making his test debut at 30.
Alama Ieremia started at 23 but wasn't considered an automatic selection at centre till the 1999 Rugby World Cup, when he was 28.
Umaga started on the wing at 24 in 1997 but it wasn't till 2001 that he developed into one of the world's best centres.
Which brings us back to Smith, who believes a centre's defensive duties are often what unravel a younger player's confidence.
"Defensively is a classic example. Compared to a flanker you will probably make only half as many tackles but your missed tackles will normally result in tries, whereas missed tackles in close might earn the opposition a couple of metres.
"As a centre, on defence you are always reacting. You can just never guarantee who you are going to tackle and you are always working off the guy inside you.
"And that might not be the second-five from phase play, often it's a loosie or a forward and you are reacting off them, so for me time in the saddle is key, along with fitness.
"There is a lot of work off the ball, bringing the chase lines up when you are chasing kicks, getting back on kicks [in support].
"A lot of it might not amount to anything like making a bust or a tackle but, if you weren't there, you'd miss opportunities on attack and you wouldn't create things for the defence, so there is a lot of unseen stuff."
It's a daunting job description but one the All Blacks will be hoping does not languish in the classifieds for long.
Kahui is the obvious answer - a hugely talented player seemingly possessing prerequisite skills and temperament but perennially cursed by injury.
Wellington's Alapati Leiua is another who leaps out as having the right mix - a player with a rare ability to read play as it unfolds in defence and attack.
And there is the talented Robbie Fruean, seemingly held back by his conditioning and a work in progress.
But, more immediately, Ben Smith is the most intriguing project. The Highlanders fullback has plenty going for him, including an innate ability to beat the first defender, strong defence, and an ability to play off those around him.
It's a safe bet Conrad Smith's namesake will get a chance at some point over the next four weeks and the incumbent is genuine in his hope that his successor can be found sooner, rather than later.
"Especially in the All Blacks you have real responsibility of that I think.
"I noticed even when I came into the side you had guys like Tana [Umaga] and Aaron Mauger, who were just super supportive of helping you get into the role and making sure you did well," Smith said.
The All Blacks have a proud heritage at centre. Toby Robson asks Conrad Smith what it takes to survive and thrive in the No 13 jersey, and wonders who might be his successor.
ALL BLACKS CENTRES, PAST AND PRESENT
Conrad Smith 2004-present Tests: 63 Debut: v Italy, 2004, age 23 Established at centre: 2008 season, age 27 Age: 31
Tana Umaga 1997-2005 Tests: 74 Debut: v Fiji, 1997, age 24 (on the left wing) Established at centre: 2001, age 28 Last test: v Scotland, age 32
Alama Ieremia 1994-2000 Tests: 30 Debut: v South Africa, 1994, age 23 (at second five-eighth) Established at centre: 1999, age 28 Last test: v South Africa, age 29
Frank Bunce 1992-1997 Tests: 55 Debut: v World XV, 1992, age 30 (at second five-eighth) Established at centre: 1992, age 30 Last test: v England, age 35 Joe Stanley 1986-1990 Tests: 27 Debut: v France, 1986, age 29 Established at centre: 1986, age 29 Last test: v Scotland, age 33
FUTURE PROSPECTS Ben Smith Tests: 9 Age: 26 Strengths: Elusive runner, smart defender, good all round skills and pace Weaknesses: Has played most of his rugby at wing or fullback
Tamati Ellison Tests: 3 Age: 29 Strengths: Experience, footwork, fend, good defender Weaknesses: Has never specialised in one position
Alapati Leiua Tests: 0 Age: 24 Strengths: Hard runner, anticipation, defensively very strong in contact Weaknesses: Behind Conrad Smith at Hurricanes where he's mainly used at wing
Robbie Fruean Tests: 0 Age: 24 Strengths: Size, explosiveness and pace to break the line Weaknesses: Can go missing during big matches
Richard Kahui Tests: 17 Age: 27 Strengths: Size, pace, skill and vision Weaknesses: Injuries
- The Dominion Post