Similar to squabbling siblings or brawling with a best mate, the All Blacks and Springboks know each other too well to pretend anything other than a classic clash of styles awaits their highly-anticipated Rugby World Cup opener in Yokohama.
The All Blacks' pace and panache against South Africa's brutal brawn, the ultimate contrast is here to give this tournament liftoff.
There have been times in the modern era of arguably rugby's greatest rivalry, specifically during Heyneke Meyer's tenure, when the Boks briefly broke from their conservative mould to challenge the All Blacks and their attacking-minded game.
Under Rassie Erasmus, though, the Boks have firmly reverted to their traditional conservative roots. Harnessing those familiar strengths they have regained their identity, respect and confidence to arrive in Japan with a clear blueprint to challenge for the World Cup.
From the fierce and fraught breakdown where the All Blacks will hope Sam Cane and Ardie Savea gain the upper hand to the set piece battle, this match will be won and lost by the eight that fronts with the attitude and intent to dominate the physical collisions for longer.
That extends to the respective benches, where the All Blacks will unleash Sonny Bill Williams, Patrick Tuipulotu, Shannon Frizell and Ofa Tuungafasi.
The All Blacks pack got the physical part badly wrong in Perth, right at Eden Park, but the Boks are an entirely different beast to the Wallabies.
Forecast rain, which had the All Blacks training with balls in buckets of water this week, will favour the Boks' forward-orientated, territory-focused approach. But it won't deter the All Blacks from their quest to use the width and offload into space.
"Even if it doesn't rain everybody is talking about the humidity and the slippery ball and the wetness of the arms so kicking is going to play a big part but somehow you have to score points," Erasmus said. "You can't just get them by penalties and dropped goals so fielding kicks and living off those bad kicks is going to play a big part."
All Blacks coach Steve Hansen knows the aerial assault Faf de Klerk will inevitably launch on the raw All Blacks back three, featuring George Bridge and Sevu Reece and their five combined starts on the wings, will play a crucial role.
"I'd say they'll kick the ball a fair bit, yeah," Hansen said. "They like to play to the 20 metres and the halfback will kick or they'll play down the short side. If they can't get to the 20 and they get stuck in the middle the halfback will kick for the corner.
"It's easy to tell what they do but it's a little harder to stop it."
In recent times South Africa's script is well worn. Only now, this is no Rugby Championship test. This is the World Cup, and a high-stakes encounter that will push the loser into an even-odds likelihood of being sent home at the quarter-finals.
The All Blacks and Springboks hold five World Cup titles between them. As these two heavyweights prepare to captivate the rugby world, nobody is certain who will prevail.
What more could you want on opening weekend?
"If you ask anybody right now who is going to win this test match I don't think anyone could bet on any of the two teams," Erasmus said.
"Our boys think they have a really good chance and if you ask Steve and his team they think they have a good chance, and hopefully the referee is not too sure.
"That's the way the World Cups should be. That's why it's special."
If there's one notion that bottles the magnitude of this match it's that no team has lost a pool match and gone on to win the World Cup.
England (1991 and 2007) and France (2011) reached the final after pool defeats but we are now in the ninth edition and the fact of unbeaten champions stands.
Records are made to be broken, of course, and the All Blacks have created more World Cup history than any nation by becoming the first to win successive titles.
Hansen made his feelings on the matter clear when he said: "It says a lot but history is only history until you change it. France went one point from changing it. If they'd beaten us in 2011 you wouldn't have asked that question and they were pretty unlucky not to get those couple of points.
"If South Africa or ourselves get beaten you've then got a choice whether you then roll over and say 'you can't win it now because we've lost this game' or you say 'well we've just got to win every other game from here on in' and if you do that you win it."
Such a mentality is entirely understandable but there is no denying any defeat brings dented confidence, a period of rebuilding and, potentially, a more difficult quarterfinal opponent.
No team wants to start a World Cup on the back foot. One of these teams will soon face that reality.
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