When the time comes for Ian Foster to reflect on 2021 and his first full season in charge, four tests will reveal more about the All Blacks than any others. Ireland in Dublin this weekend is one.
From a development cycle point of view, Foster's All Blacks are in catch up mode after last year's Covid-disrupted season reduced his maiden campaign as head coach to six tests.
A 50 per cent win record in 2020 heightened scrutiny and pressure on Foster and yet, to this point at least, the All Blacks have largely navigated the challenges associated with being confined to a restrictive, elongated touring bubble as well as could be expected.
In terms of shaping his first-choice team and strategies to counter the biggest challenges in the world game successive tests against the Springboks were invaluable. So, too, are the final tests of the year against Ireland and France.
While Foster's squad to face Ireland features a smattering of inexperience - loose forwards Ethan Blackadder, Dalton Papalii and wings Sevu Reece and Will Jordan boasting limited exposure to Northern Hemisphere foes - the vast majority of the All Blacks know exactly what's coming this weekend.
Six starters featured in the last test in Dublin and Foster has named the same tight-five from the 2019 World Cup quarterfinal.
Brodie Retallick, one of the most niggly, competitive trainers, revealing plenty of friendly fire elbows have been flying from the All Blacks this week is a good sign. Combative trainings only adds to a sense the All Blacks are ready to rise for an examination that will be integral to shaping Foster's squad for the years to come.
Despite the late stage of the season there are no fatigue excuses for the All Blacks. Foster has managed his squad throughout the year, designing rotation specifically with this peak in mind.
Question marks remain around the new-look Anton Lienert-Brown-Rieko Ioane midfield; how the All Blacks will cope with Ireland's physicality, breakdown and defensive pressure. At this point in his tenure, these are precisely the questions Foster needs answered.
"There's no denying it's the second block of five tests in a row but am I excited about our preparedness? Yeah I am," Foster said.
"We're as ready as we can be for this game and we're certainty not lacking in any motivation. These are the big stages that we seek. We're still a developing team to be honest, still growing what we want to do. These are the games you put a marker down and you get the answers to where you're at in some aspects.
"It's about the players, the strategies and how you adapt in a game because we know there will be situations chucked at us that will be new to this particular group and we're going to have to deal with that."
Anyone underestimating Ireland has no grasp of recent history. From a results perspective, Ireland have become one of the All Blacks' great modern-day foes.
Most pinpoint Ireland ending their 111-year wait for victory over the All Blacks in 2016 in Chicago as the moment this rugby relationship shifted on its axis. The truth is the seeds of belief that fuelled that upset were sown three years earlier in Dublin, when the All Blacks pulled off their great escape.
Sure, the All Blacks dismantled Joe Schmidt's Ireland when it mattered most in the World Cup quarterfinal but their last meeting in Dublin is much more pertinent for the rivalry's resumption this weekend. As the All Blacks discovered that day, playing before a sold out Aviva Stadium can be a daunting experience when on the backfoot.
"The relevance of 2018 is we don't like losing," Foster recalled. "What we've learnt, and we've felt this with teams up here before, is they've got big crowds that get in behind their team and feed off any sense of hesitation or weakness from visiting teams."
Of those with the most to gain it's hard to overlook rookie blindside Ethan Blackadder. Having surpassed Akira Ioane in the Springboks tests he now gets another chance to put his stamp on the six jersey.
"It's a very physical, close quarter game up here and that suits him," Foster said. "He's got a lot of energy. He's uncompromising in what he does and he's adding the skill part to his game all the time. We know it's going to be a battle up front. The Irish are a tough pack. The breakdown is important; the quality of your ball carrying and defence is important and in a couple of those areas, Ethan has made quite an impact for us."
Ireland, under Andy Farrell the past two years, are increasingly attempting to evolve their formulaic attacking game.
Retaining former Hurricanes and Blues halfback Jamison Gibson-Park, after impressing in the nine-try mauling of Japan last week, over veteran Conor Murray points to Ireland playing more than in recent years, though recalling Lions lock Iain Henderson ultimately speaks to where this battle will be determined.
Farrell will be well aware a fast-paced expansive match is far more suited to the All Blacks.
"What we are seeing is an expansion and ambition of what they want to do with the ball," Foster said. "They seem to be more at ease about taking opportunities wider and being comfortable playing like that. It just means you've got to open your eyes and be aware they've got more threats in attack they what they had 24 months ago."
All Blacks team:
Jordie Barrett, Will Jordan, Rieko Ioane, Anton Lienert-Brown, Sevu Reece, Beauden Barrett, TJ Perenara, Ardie Savea, Dalton Papalii, Ethan Blackadder, Sam Whitelock (c), Brodie Retallick, Nepo Laulala, Codie Taylor, Joe Moody.
Reserves: Dane Coles, Karl Tu'inukuafe, Tyrel Lomax, Tupou Vaa'i, Akira Ioane, Finlay Christie, Richie Mo'unga, David Havili.
Ireland:
Hugo Keenan, Andrew Conway, Garry Ringrose, Bundee Aki, James Lowe, Jonathan Sexton (c), Jamison Gibson-Park, Jack Conan, Josh van der Flier, Caelan Doris, James Ryan, Iain Henderson, Tadhg Furlong, Ronan Kelleher, Andrew Porter.
Reserves: Rob Sheehan, Cian Healy, Finlay Bealham, Tadhg Beirne, Peter O'Mahony, Conor Murray, Joey Carbery, Keith Earls.
The missing rugby jersey was found after a two-year search.