There's clearly a bit of ill-feeling in Ireland about the way things played out the last time the All Blacks were in Dublin.
It was an unforgettably brutal test that saw three Irishmen concussed, two All Blacks yellow carded and an edgy post-match interview where Steve Hansen asked his questioner if she was trying to get him to admit he was in charge of a dirty team.
The day after the All Blacks' 21-9 victory, Irish team manager Mick Kearney suggested 12 incidents had been put in front of the citing commissioner, 11 of which had been committed by the All Blacks.
Two incidents in particular had upset the Irish: the first was early in the game when Sam Cane's shoulder collected Robbie Henshaw's head in a clash that the officials saw as accidental but the crowd didn't.
And the second was a high tackle by Malakai Fekitoa on Simon Zebo after 60 minutes that was yellow carded when a judicial panel later ruled it should have been red.
On balance, the Irish had good reason to feel a touch aggrieved as the result may well have been different had the All Blacks been forced to play out the whole of the last quarter rather than half of it with 14 men.
The fact it was Fekitoa, back after his spell in the bin, who scored the All Blacks decisive third try only fuelled the sense of injustice.
It's not quite water under the bridge, as evidenced on Monday when Ireland's talismanic first-five Johnny Sexton said about that game: "It was physical. I think that game probably went over the edge.
"But I think it did change a lot going forward. It was a massive game where high tackles were assessed in terms of what was acceptable and what was not. After that, I feel things changed."
It was, indeed, a watershed game in the sense it heightened the need for World Rugby to lower the tackle point and for referees to be stronger in policing contact with the head.
And Sexton was also right when he said: "In some ways it was a sign of respect. They may have been hurting from a few weeks previously. But you only get the respect if you beat them. You feel that when you beat them."
The All Blacks were hurting after losing to Ireland in Chicago two weeks earlier.
That loss got into a few All Blacks' heads and their response when they met Ireland again two weeks later was to rely too heavily on their fury to extract the victory they craved.
The All Blacks were too much bludgeon, not enough rapier and they learned as much in beating Ireland as they did losing to them.
"We went out there and really tried to bash them and we ended up making so many tackles and played the game that way. It was a gutsy win," Cane said a few weeks ago.
"What I learned from that is we don't want to go out there and bash them. Use our skill-set, some of our game management things we learned and play smart as well as physical."
And that's helping this game generate as much interest as it is. The All Blacks, in their inimitable way, had an honest review after that test in Dublin and accepted the need to be more balanced in their approach: to understand that they can hurt teams as much with their movement and timing as they can their physical intent.
They know that to win in Dublin again they will need to find the right mix of physicality and creativity.
The red mist can't come down and blind them to space and opportunity. Their offloading has to be prominent, so too their subtle slip passes that often put the big runners into holes.
But nor can they afford to be passive. They can't concede an inch to Ireland in any of the collision areas and they can't buy entirely into what is a slightly altered narrative of what happened in 2016.
The inference has been strong in the Irish view of what happened in 2016 that they were guiltless victims.
Which is not quite true. Sexton himself would, in the current regime of zero tolerance, have been yellow carded possibly even sent off if he lucked out with a jittery official for his attempted try-saving tackle on Beauden Barrett in the first half.
and neck rolls and maybe they didn't quite give as good as they got, but they frequently strayed on the wrong side of the metaphorical line.
As Barrett noted wryly on Tuesday: "I remember the Irish being pretty aggressive as well."
And the question for Ireland is the same as it is for the All Blacks – can they, too, find the right tone on Saturday? Stand up to the All Blacks but not overdo the intimidation and enforcement?
Can they avoid falling into the trap of letting lingering resentment trick them into thinking they need to exact some kind of below the line revenge for 2016?
Rarely does a test have such a great back story – a kind of Russian doll history where there is drama stacked upon drama and the near certainty that more will be added on Sunday morning.