Hansen has proven himself to be a master of transition
Barring the unlikeliest of crises, when Steve Hansen says goodbye to the All Blacks next year his win percentage as head coach should sit somewhere in the low 90s.
That would be a better return than his predecessor Graham Henry (85pc), who Hansen worked under as an assistant during the Rugby World Cup disaster in 2007 against France through to redemption four years later on home soil.
Combining that stint as a lieutenant with his role in the top job since 2012, Hansen will have given 15 years of his life to coaching New Zealand by the end of the tournament in Japan. Quite understandably, the time has come for a break.
The former police officer can come across as a little gruff and bristle when faced with a jumbled question in a press conference, but behind that front lies a warm character who thrives off turning talented players into great All Blacks.
The emotion he showed speaking to TVNZ's John Campbell after yesterday's announcement was a compelling insight into the man behind the team who have remained at No 1 in the world throughout his time in charge.
"You are not just a rugby coach," said Hansen. "You are a person coach."
When prompted about how much the support of his wife, Tash, meant to him, Hansen could only muster the word "everything" before fighting back the lump in his throat and taking a minute to compose himself.
Should New Zealand win their third Rugby World Cup in a row in Japan then that is obviously how Hansen will be remembered, but his real triumph has been the evolution of the All Blacks under his watch from the Richie McCaw-Dan Carter-Ma'a Nonu-Conrad Smith era into the side today built around Beauden Barrett, Brodie Retallick, Sam Whitelock, Kieran Read and Ben Smith.
Barrett and Retallick's path to becoming focal points of the side is no accident, managed expertly over the years by Hansen. Both were handed their debuts in 2012, as was the case with Richie McCaw's successor Sam Cane.
Managing the retirements of arguably the greatest All Black of them all, McCaw, and one of the all-time great fly-halves in Carter has been a masterclass in succession planning.
Hansen equally has also never been afraid to throw young players into the deep end, as was the case with Rieko Ioane before the 2017 Lions series.
When the time has been right for players to be moved on, Julian Savea for example, the tough call has been made.
His sense for when a player is ready to be an All Black, and when they are not, has become a fine art.
Under Hansen's watch, coaching the All Blacks has become a shared operation with his assistants Ian Foster and previously Wayne Smith, now Scott Macleod.
His record as head coach is remarkable: 96 Tests have yielded 85 victories, three draws and just eight defeats (two to Ireland, one to England, one to the Lions, two to South Africa and two to Australia), plus a Rugby World Cup crown in 2015.
Winning the Rugby World Cup will now seem like the perfect swansong for the 59-year-old.
Ireland pose a genuine threat, with Wales, England and South Africa also in the frame. But everybody expects one team to triumph more than any other.
It is to Hansen's immense credit that throughout his tenure, as world class All Blacks have come and gone and rival nations have threatened, New Zealand have always been out in front.
© Daily Telegraph, London