Wales are the reigning champions. They won five out of five in 2019, meaning they also claimed the Grand Slam (for beating every team) and Triple Crown (for beating the other 'Home Nations', ie England, Scotland and Ireland).
The form book from last year's tournament can mostly be thrown out, however, considering a large factor in deciphering the respective form of each team reared its head last November: the World Cup in Japan.
England, despite the disappointing final loss, were the side to come out of the tournament with most credit, especially after that emphatic dispatching of New Zealand in the semi-final; Wales could not get past eventual winners South Africa in the semi-final; Ireland and France fell at the quarter-finals; while Scotland and Italy did not progress from a Typhoon Hagibis-hit pool stage.
But how are the Six Nations odds looking for this year's edition? Let's take a look as the opening round approaches.
Favourites - England 10/11
Eddie Jones has stuck with a large proportion of his World Cup heroes, while at the same time taking the opportunity to instill some fresh blood into the ranks - with uncapped players making up more than a quarter of his squad.
Jack Nowell will miss out after undergoing an ankle operation, while it was confirmed that Billy Vunipola suffered a broken arm in Saracens’ 27-24 victory against Racing 92.
It remains to be seen how much that dismal World Cup final defeat, coupled with Saracens' salary-cap furore, will affect Jones' squad. They open the tournament against a rejuvenated France in Paris; negotiate that challenge and the momentum will be all with them as their biggest rivals with the bookmakers - Ireland and Wales - both have to travel to Twickenham.
Of the six teams, England are favourites with the bookies for the Grand Slam, too, although no winner has the shortest odds.
The era of Joe Schmidt has ended, and former Rugby League Man of Steel and Saracens centre, Andy Farrell, has taken the reins of the Ireland team. Just over a year ago, Ireland were No 1 in the world and had just conquered the All Blacks. In 2019, however, their form took a dramatic turn; after England gave them a though-provoking whipping at Twickenham in a World Cup warm-up match, they lost to Japan and New Zealand to once again fall at the quarter-final stage of rugby's blue riband tournament.
Farrell's first move in his bid to take Ireland from one-off world beaters to consistent conquerors was to appoint influential fly-half Johnny Sexton as captain, just for this tournament initially, after the retirement of long-lasting hooker Rory Best. Farrell has also refreshed the squad; Leinster’s 21-year-old hooker Ronan Kelleher and back-row forwards Caelan Doris and Max Deegan join Ulster prop Tom O’Toole and former England age group fly-half Billy Burns as the uncapped players in the squad.
He has also taken a leaf out of Eddie Jones' book and included some 'development' players; those for the future whose chances of playing in this tournament are slim but not obsolete.
Regardless, the first weekend of the tournament often sets the tone for what's to come. If Ireland can put Scotland to the sword in Dublin, as they did in the World Cup pool stages, then they might well consider themselves contenders.
Warren Gatland was one of Wales' most-successful ever coaches, winning three Grand Slams in his tenure from 2007 to 2019. They are now entering into a slight period of unknown, but they have kept hold of the core of the squad that got to the World Cup semi-finals last year.
Although inspirational centre Jonathan Davies has been ruled out for Wales, good news comes in the form of Toby Faletau's return, and Liam Williams' earlier-than-expected reintroduction to the squad. The Saracens full-back, who is heading back to Wales at the end of the season, will play at least some part in this campaign for new coach Wayne Pivac.
Pivac is a shrewd rugby operator, too, and enjoyed periods of great success at the Scarlets, who became renowned for their high-tempo, high-skill-level, high-risk rugby.
The totemic Alun Wyn Jones will continue as captain while he continues to perform at the highest level. The youngsters are keeping him fresh, too; Gloucester wing Louis Rees-Zammit is almost half the age of the Welsh captain.
Ordinarily, you would just have to ask 'where to even begin?'. Now though, with a new coaching staff and a new captain, there is renewed optimism for France. Toulon flanker Charles Ollivon will captain the side, while Fabien Galthié, assisted by Shaun Edwards, will coach.
Ollivon, 26, was a try-scorer in the World Cup quarter-final defeat against Wales last year, where Sebastien Vahaamahina had his moment of madness in a match that France could and should have won. Ollivon succeeds Guilhem Guirado, who retired from international rugby following the World Cup.
At 7/1, with England and Ireland at home, a refreshed, determined France might be worth a flutter.
Galthié has selected one of the most youthful-looking French squads for years, seemingly willing to reward strong domestic showings with international recognition - something which has not always been a pre-requisite with French national selections.
A number of senior backs have been left out, including Maxime Médard and Yoann Huget, as well as regular half-backs Morgan Parra and Camille Lopez.
But the back-line is set to buzz with electricity regardless. A back division featuring Antoine Dupont, Romain Ntamack, Virimi Vakatawa, Teddy Thomas and the irrepressible Damien Penaud will give more than a few scares to the rest of the field.
Finn Russell's dramatic exit from the Scotland squad may well have played a part in this but, in truth, all of the optimism surrounding Gregor Townsend's premiership with Scotland was dampened by a desperately disappointing World Cup campaign in which they were knocked out in the final round of the pool stages by host nation Japan.
Following the retirement of Greig Laidlaw, announcing hot-stepping full-back Stuart Hogg as captain is a sign of continuity if nothing else, but with only two home games - against England and France - this could be another sobering season for Scottish rugby.
Italy are in a rebuilding phase, with an interim head coach and the imminent retirement of stalwart Sergio Parisse. They should not be written off entirely, however, from winning one match at least. In Jake Polledri they possess perhaps the tournament's pre-eminent ball-carrier, and they will be desperate to give the legendary Parisse a fond farewell.
Jonny May is ubiquitous at the top of this list, and odds of 4/1 for him make him the favourite in this market, as he attempted to follow-on from last year's success, where his six tries were enough to keep him at the top of the pile.
But Josh Adams of Wales is the next best candidate with the bookies, presumably due to his topping of the try-scoring charts at the World Cup in Japan. Odds of 9/2 for him, when put alongside the more expansive game that Wales might attempt with new man Wayne Pivac at the helm, may well be worth a punt.
Teddy Thomas has been out of international favour for several years but rarely does a week go by where he is not making headlines for either his finishing or his skill level. Clearly, despite his recent international exclusion, the bookies agree. He's 10/1.
At 22/1, Virimi Vakatawa could be the dark horse for this market. His domestic form for Racing 92 has been scintillating, but this prize is traditionally won by wings (eight of the last 10 years).
Owen Farrell, Dan Biggar, and Johnny Sexton are virtually inseparable at the summit of the top points-scorer market, incidentally.