THIS is a story of two teams with very different World Cup traditions, of two sides whose relationship with this tournament varies wildly.
The champions sit with an unbeaten record in knockout rugby since 2007; a blend of old-stagers with World Cup medals in their back pockets and young hot shots ready to announce themselves on this stage and a tradition of excellence going back a century or more.
Up against them are a team that have never won a knockout match, a side that have perennially failed to land a blow when it matters most but a collection of players who have built steadily towards a point where they believe they can break a glass ceiling that has loomed above them since 1987.
Only the men of 1991 came even close to scratching that seemingly impenetrable dome.
If Joe Schmidt’s class of 2019 are to reach the win tomorrow, it will go down as Ireland’s greatest victory.
Schmidt is always aware of the odds and he’ll have taken note of the 12-point margin the bookies are predicting.
Twice this week, he has warned that his team can play to their potential and lose this match because New Zealand are so good.
Even in the dominant 2018 win in Dublin, Ireland needed a series of miracle plays to keep the world champions try-less.
That, like all four of the matches played in the Kiwi’s time in charge, was played in November and, although the forecast is for a very Irish day in Tokyo, the men in black will be in fresher form than they’ve been in all four of those matches.
This is their peak and they have a well-worn model for arriving at this point and delivering a performance.
In 2011, they put 33 points on Argentina to win comfortably and four years later they laid down a statement performance against France to secure a 62-13 win.
That was a different team. The leaders of that golden age largely retired in the aftermath of their back-to-back success and Steve Hansen has regenerated from a superb production line.
They have the best players and play the best brand of rugby, but over the past six years they’ve found no opponent as difficult to play against as Ireland and that is why the men in green will go into this match with the belief that they can take the All Blacks into a place they don’t want to go.
In Chicago, they scored five tries and in Dublin they mustered one, but the champions have evolved their attacking play since these teams last met.
Ireland dealt well with their dual-play-makers when it was Damian McKenzie at full-back and Beauden Barrett at out-half, but the combination of Crusaders star Richie Mo’unga at No 10 and Barrett out the back is a different one.
Throw in the aerial ability of George Bridge and the footwork and explosiveness on the edge of their controversial new flier Sevu Reece and it’s an altered picture.
Up front, they’ve changed their props, partly as a result of the lack of dynamism they got from Karl Tu’inukuafe and Owen Franks and the combination of Joe Moody and Nepo Laulala is a much more serious proposition around the park.
Much will depend on the second-row, where Iain Henderson needs to deliver one of his best performances alongside the consistent James Ryan.
They are up against the world-leading pairing of Brodie Retallick and Sam Whitelock, but the Irish duo do possess a battle-hardness that can count in their favour.
If Ireland have the edge in the tight-five and half-back, the All Blacks are in a different class in the back-row where Peter O’Mahony, Josh van der Flier and CJ Stander’s mission is to out-work and out-fight a class trio.
If they can win those battles, then it will come down to taking their chances.
So far in this tournament, Ireland have largely ignored kicks at goal and gone for the jugular but cup rugby necessitates a change in approach.
Wales showed against Australia that there is a merit in keeping the scoreboard moving and taking the three points.
With rain forecast for Tokyo during the day tomorrow, handling will be under pressure and every chance to score should be taken.
Ireland need their scrum to be dominant and their lineout to run well. Clean possession out of touch is the life-blood of their game and if the All Blacks deny them that access into the match they could struggle for oxygen.
Sexton will target Reece’s positioning, while they’ll also look to isolate Mo’unga in the defensive line and get their ball-carriers attacking his channel.
They will look to Schmidt’s special plays to get in behind the champions and, when they get there, they must take every opportunity to build a score.
If they don’t, they leave themselves vulnerable to the most dangerous team in the world.
As they showed against South Africa when they weathered an early storm, the All Blacks have the talent and application to rip any team apart.
In 2018, Ireland were able to sustain their physicality through 80 minutes of relentless possession rugby.
Ian Foster said on Thursday they were able to suffocate teams, but that hasn’t been their strength this year.
Without Dan Leavy, their capacity to win collisions has waned and they need to be smarter in possession.
When they don’t have the ball, they must be smart in identifying which rucks to target and otherwise fan out and make their tackles.
Andy Farrell’s defence has been equal to this task in the past and Ireland have been the best rearguard team at this World Cup.
Whether it’s enough to hold out the best attack remains the challenge.
Certainly, they can’t afford to hand possession to the men in black and hope to make an endless succession of tackles.
Instead, they must play Joe Schmidt rugby to the best of their ability.
For two seasons, they have referenced the fact they have been chasing the perfect game.
It is an unattainable goal, there is always room to improve, but it has been noticeable that this team has strived to get to that level.
Thus far in 2019, they’ve been way off.
It’s been almost a year since they produced anything close to their best against a team of their own standing.
Today has to be the day or else they will say goodbye to the coach and end a glittering era with the same result as every other Irish team that has gone before them.
This side and this coach are supposed to be different.
Unlike four years ago, their squad is largely intact and the leadership group is fit and available.
Today, New Zealand have the capacity to cut loose in exactly the same way but Ireland will expect a very different performance. But they are not as good as they used to be and Ireland have the know-how to beat them.
They’ll know history is in their grasp but they’ll also be cognisant of the fact that this will take a performance of unmatched quality to take them into that territory. They need to get everything right and even that may not be enough to dethrone the champions.
Rugby World Cup 2019
Just after 12 noon in Port Elizabeth on Saturday, a Southern Kings second row will sit down, on his own, and turn on possibly the most important rugby match Ireland have ever played.