Ireland, as it turns out, didn't do themselves any favours by beating the All Blacks last November.
They planted their foot in history: got their chalk mark scrawled on the wall that said for the second time they had beaten the mighty All Blacks.
It brought a short, glorious cause for celebration. It brought a night of great craic and hopes of something more – the promise that Ireland were edging past New Zealand as the team to beat at the Rugby World Cup.
For that brief moment in time, Ireland had everyone's attention: they were the team that had found the magic formula to beat the All Blacks.
They had won two tests against the All Blacks in their last three attempts, so it was no longer a case of them getting lucky.
They had the players. The smart coach and the clever gameplan that was low risk yet delivering high reward. And they had the All Blacks rattled.
A team that had begun the World Cup cycle in 2016 scoring almost six tries per game, couldn't get over the line once in Dublin.
Ireland defended as if they had cloned a few extra players and for 80 minutes they fired off the line and didn't relent.
It was a defeat that hurt the All Blacks more than they could let on. And it hurt because Ireland prevented them from being the very thing that they are: a free-spirited, attacking team with an imagination that has no bounds.
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Yet there they were in Dublin, clunking into green jerseys and looking increasingly like a team that had been robbed of its soul by something as simple as a well-organised defence.
The All Blacks felt like the kid who had been tricked by Ireland into thinking their shoelaces were undone, only to be smacked in the nose when they were stupid enough to look down and check.
Ireland had the one trick and it was good enough to reduce the All Blacks to a faltering mess. Ireland were effective, but they were also supremely limited and that was the real fear.
Ireland's blueprint is so basic that they could hardly lock up their intellectual property by slapping a patent on it.
Others would see and others would copy and potentially those who replicated would reap the rewards.
But what Ireland may perhaps not realise is that their victory did much more for the All Blacks than it did them.
It instilled in the All Blacks a ferocious desire to rebuild their attack game and exact not so much a terrible revenge in Japan as one that would be inspired, creative and innovative.
It forced the All Blacks to look harder at what they were doing and why their attack was faltering against line-speed.
And so there's no doubt that the All Blacks have selected a phoenix team for the quarter-final – one that rose from the ashes of that 16-9 loss to Ireland 11 months ago.
It was that loss in Dublin which confirmed in coach Steve Hansen's mind that if they were going to win the World Cup, they had to pick Richie Mo'unga at No 10 and shift Beauden Barrett to fullback.
The All Blacks needed better decision-making to break defences and introducing Mo'unga would up the strategic horsepower.
Barrett at fullback would change the profile of the back three – give them the sort of kick-catch skills they were missing, as well as the devastating speed and awareness to punish anything that fell into the wrong area.
More generally, though, the defeat sowed the seed in Hansen's mind that if Ireland and others were throwing everything into their defence then the All Blacks had to respond by throwing everything into their attack.
Experience wouldn't be such a factor in their thinking and selections would be governed more by who could use the ball best.
Who would give them the best chance of unpicking a well-organised defence and delivering the all-out attack game they were now after?
Hence Anton Lienert-Brown and Jack Goodhue are in the midfield – the former somewhat obviously given his incredible form and range of skills, the latter because he is the best distributor and creator and exploiter of space.
Sevu Reece and George Bridge don't appear to have any fear of any defensive system and play with such instinct that they will transfer the decision-making pressure to Ireland's defenders.
Ardie Savea at blindside gives the All Blacks the ball-winning capacity they didn't have in Dublin and the threat of attacking more regularly against an unstructured rather than structured defensive line.
The team Ireland faced last year is not remotely similar to the one they will play in Tokyo this weekend and they can perhaps feel some sense of pride that they were the ones to force the transition.
But that may be short-lived if it turns out that what Ireland really did last year was give the All Blacks the answer to the one question that they posed.