Here, PA examines the nuts and bolts of the big machines' attacking approaches.
Trendsetters to the point where other Test coaches clip up their exemplary patterns of play to map out ideological aspirations – not just to their own squads, but sometimes to members of the media too. Stuart Lancaster did just that as England boss when underscoring lock Brodie Retallick's all-court skills as an auxiliary playmaker. Some six years after Lancaster's power point heralding, Retallick remains so pivotal to the All Blacks that boss Steve Hansen selected him for the World Cup knowing he might not feature until the quarter-finals due to a dislocated shoulder. If Retallick remoulded tight-five forwards into ballers, hookers Dane Coles and Codie Taylor boast the pace and guile to lurk with genuine creative intent in the channel outside 13. Beauden Barrett offers searing pace at fly-half, or another playmaking option from full-back should Hansen start Richie Mo'unga at 10.
All of a sudden equal parts power and panache, at once flexing muscle and flicking passes thanks to their fit-again titans. Vunipolas Mako and Billy, Maro Itoje, Manu Tuilagi and Joe Cokanasiga can all pop as many sinews as back-door passes. Partner all those talents and Eddie Jones can wield a third of a team in powerhouses alone. Add in George Ford, Owen Farrell, Henry Slade and Elliot Daly with the swashbuckling playmaking ability, and boss Jones' men boast the all-court game to swipe the Webb Ellis Cup. England have hardly had all these talents fit at the same time. Keeping them all fresh and firing will be just as big a challenge as blending bludgeon and rapier in seamless fashion.
Full metal jacket physicality and emotional fire that can suppress any team in the world. To characterise this Warren Gatland team as one paced would be hugely foolish and it must be assumed the Test arena has long since given up attempting to patronise the savvy Kiwi by branding his teams in any way limited. Gareth Anscombe's loss to injury a blow but Dan Biggar can boss proceedings from 10, dictating a relentless tempo to grind opponents into submission. Expect power runners off both shoulders of both half-backs, and more strike men lurking out wide too. Gatland's parting shot as Wales boss could yet be his finest hour.
Everything rests on half-backs Conor Murray and Johnny Sexton. If the British and Irish Lions playmakers are fit and firing, Ireland could rule the world. If not, another quarter-final par performance is just as likely. Munster's Murray has all the credentials to boss Joe Schmidt's backline as a French-style petit general. Robbie Henshaw's power at inside centre means if Murray and Sexton get into the groove, expect to see both men looping on repeat through the inside back cordon in phase play. Murray can ghost through the 10 channel allowing Sexton to float out to 12, sending Ireland's strike runners wider still – and forcing defences into a catch-up cover scramble.
Moulded in the image of their head coach and one-time scheming Test fly-half Gregor Townsend, Scotland have so many wide threats they cannot wait to put width on the ball and stretch opponents. Fly-half Finn Russell and full-back Stuart Hogg are always itching to put some air on their rangy passes and will hope the humid, dry weather and hard pitches will help their top-of-the-ground running. Prop WP Nel will be crucial to anchoring an at-times vulnerable scrum.
Shambolic at times in the last 18 months, somehow Michael Cheika has shaken his Wallabies into a threat again. James O'Connor's return and his deployment at outside centre could prove crucial. The former Sale star is a genuine playmaking threat, and lurking in the wider channels he could catch out any narrow defences in a flash. Christian Lealiifano has jumped from fighting off leukaemia to bossing the Australian backline. The well-regarded and much-liked fly-half has the guts to stand flat and cop plenty of punishment to send team-mates into space. Must still find a way to negate lack of raw power up front, but a threat nonetheless.
Bursting at the seams with power and ready to make mincemeat out of anything in the way. Increasingly fluid attacking rhythm however, with Sale's scrum-half dynamo Faf De Klerk at the heart of all that. De Klerk hits way above his weight and drives the Springboks on and on while other inferior engines splutter and fail around him. Veteran hooker Schalk Brits could add a centre's abilities off the bench but always brings an infectiously-upbeat personality, while Toulouse wing Cheslin Kolbe's footwork mesmerises and stuns in equal measure.