The border question that rages across Ireland concerns not politics but sport, its focus centred on whether Joe Schmidt's side can transcend long-established frontiers and lay claim to being the best team in the world.
No matter that the official rankings will have New Zealand at the top of the tree irrelevant of the result at the Aviva Stadium. No matter that the All Blacks will head to Japan in 10 months' time as favourites given the dominance of their performances since the last tournament. All that is to be put to one side, mere footnotes to the grand debate.
This game is about cementing the list of true contenders, of determining real possibilities, of seeing whether Ireland are made of the right stuff. This is an opportunity to reach out and draw a new horizon. They have the capability. As Grand Slam champions of Europe and on a run of a record 10 successive victories at home, their credentials are impeccable. Yet they have beaten New Zealand only once in 113 years. The case needs still to be proven. Sunday morning (NZT) is that time.
New Zealand certainly see it in that context, 'No 1-ranked team against No 2', a heavyweight promoter's dream billing, prime-time entertainment. The All Blacks are aware, too, that they face yet another stiff examination of their own status, as well as of their endurance, towards the end of a draining year on rugby's international treadmill. Head coach Steve Hansen has been here many times before and has witnessed the enhanced ferocity that opponents routinely manage to bring to the occasion.
"Everybody we play has the game of their lives against us because we're the team that they want to beat and they get up for it," said Hansen. "They are playing 10 per cent better from the get-go."
As a makeshift England side showed last week, the opposition know deep within that if they do not hit the heights themselves, they run the risk of being shredded. England took the initiative but could not see it through. Never mind the farrago of the TMO, England did not have the composure or savvy to close out the game as the All Blacks did so thrillingly in Dublin five years ago when they won the match with a Ryan Crotty try deep into added time.
Having suffered at the sharp end, Ireland are on full alert for such painful eventualities. However, so are New Zealand. They might claim that they are so before each and every Test match, paying due homage to the legacy of the black jersey. But there are opponents and there are opponents. Ireland are trading on a level footing, an established force in their own right, one-time victors, too, over the All Blacks, winning 40-29 in Chicago in 2016. This is a contest of super-fine margins, so much so that Ireland head coach Joe Schmidt, normally such a stickler for precision, states that, "Any old win would do... I'd take 3-0."
This is an evening where the result is paramount, not the performance. Of course, the former will not happen without the latter, for New Zealand's standards rarely slip. Schmidt, too, will have schooled his men to within an inch of perfection. It is not only the entire rugby-leaning population of Ireland that will be studying Schmidt's input, so too will great swathes of people in the early hours of Sunday morning 12,000 miles away in New Zealand. Schmidt is the favoured one in the eyes of many to succeed Hansen in the wake of next year's Rugby World Cup, although Hansen's long-standing right-hand man, Ian Foster, might have a few things to say about that.
Schmidt is known for his meticulous planning. Even though Hansen believes that his fellow Kiwi will have 'a trick or two' up his sleeve, the reality is that Ireland play to strict patterns. As Hansen noted, they keep the ball longer than any other team, looking to 'suffocate' you. That is as may be. But it does not tell the whole story. Far from it. Ireland have plenty of opportunist talent in their ranks, be it the feet of Garry Ringrose in the centre or the fast-moving menace that is wing Jacob Stockdale.
Of course the absence of scrum-half Conor Murray and centre Robbie Henshaw is a loss. But Ireland have depth (as England did) and look equipped to take the game to the All Blacks. Toner's role at the lineout will be key, marshalling his own men and attempting to disrupt that pre-eminent New Zealand duo of Sam Whitelock and Brodie Retallick, playing their 50th Test together. Schmidt has complete faith in Toner's abilities having selected him more times than any other player (55 from 60 Tests). Saturday is payback time.
After losing to South Africa this year and escaping twice by pip-squeak margins against the Boks and England, there may well be an air of vulnerability about the All Blacks but it is a relative one. Damian McKenzie was iffy at times at Twickenham but a world-beater at others.
Ireland know that they will be under duress but in Andy Farrell they have a defence coach who has helped oversee victory three times over the All Blacks (with England, Ireland and the Lions) in the last six years.
New Zealand will have to be at their peak to win, Ireland likewise. It is a summit of equals.