Seldom do the stars align for both sides in direct confrontation on the final day to both be in title contention, and the atmosphere inside the Millennium Stadium will be at fever pitch come kick-off at 1700 GMT.
England simply need a victory, while Wales must win by at least seven points if they are to become only the third team - after England in 2001, and France in 2007 - to retain the Six Nations title.
So who is going to win? Current and former players and coaches have all had their say this week.
Former England coach Sir Clive Woodward:
"My heart says England, my head says Wales will probably go in as favourites. But England have nothing to lose now. They have to forget about this Grand Slam stuff and get into the mind-set of scoring tries. They just have to get their head in gear for what will be a colossal game. I can't wait."
Former Wales wing Shane Williams:
"I will be happy with a Wales win, whether it is by one point or eight. I think it is going to be very tight. I don't know whether we will get the seven or eight points we need, but I think we will pip them."
An England victory by any margin would secure a first
triumph in a decade.
An England defeat by six points or fewer would be enough for
ENGLAND TO WIN THE TITLE.
If England lose by seven points but outscore Wales by three tries or more,
ENGLAND WIN THE TITLE.
A Wales victory by seven points or more, providing they stay ahead of England on tournament tries (7 to 5 so far), would see
WALES RETAIN THE TITLE.
If Wales win by seven points but England score two more tries then the
TITLE WOULD BE SHARED.
Former Scotland captain Andy Nicol:
"Wales know that if they play well, they can beat England by more than enough to win the championship. I think it will be a cracking game, very intense and physical. They won't necessarily be throwing the ball around too much but it is going to be brilliant to watch. England have the game to win down in Cardiff but Wales are growing in confidence and have a really potent backline. I think the Welsh pack will want to take on this English one, but I think England could be too strong, just, and sneak it."
Italy captain Sergio Parisse:
"Wales in Cardiff is going to be difficult for them but for the whole tournament, I think England deserve to win this Six Nations."
Former England scrum-half Matt Dawson:
"My concern is Wales will just be focused on winning the game, and that's all. I think it will be a mountain to climb for England. Even though I would love to see them win, I think Wales' experience might make it a step too far for England."
Former Wales flanker Martyn Williams:
"Our boys have been there and done it before, as have the coaches, and will know exactly how to prepare them for this game. They also had an extra day to prepare, which is a huge advantage. I just feel everything is falling in our favour. I think Wales will win, and win the championship as well."
Former Wales fly-half Jonathan Davies:
"Wales got their confidence back with
that win in Paris.
They didn't become a bad side overnight, just as England didn't with
that performance against Italy.
They will still come to Cardiff confident. If Wales have the ascendancy with 20 minutes to go, there may come a time when they have to make a tactical decision about the points margin. But first and foremost they just have to go out with the attitude of winning the game. They haven't won for a long time at home but I still think home advantage in this game will favour Wales."
Six Nations: England's Grand Slam glories
Former England captain Will Carling:
"My heart says one thing, but if I am being really honest, I would be surprised if Wales don't win the game. I think this Welsh side has much more experience in them in the Six Nations, and I think that counts for a lot. They are at home, in a great stadium, and that might just give them the edge."
Italy full-back Andrea Masi:
"It's going to be a tough game, but I think England are a bit more dangerous than Wales."
Former Wales captain Gwyn Jones:
"Our boys have been in this position before with
Grand Slam deciders
and the semi-final of the World Cup. This England side hasn't been anywhere near this sort of pressure situation before. I think it will be a tight game, but there is nothing to fear for Wales."
Former England and Scotland coach Andy Robinson:
"I think England will win the Grand Slam. They have the game, and the firepower, to match Wales physically. It has been a long time since Wales won at home and there will be a bit of doubt at the back of their minds. I think England will come with real confidence and try to play at a real pace."
Former England centre Jeremy Guscott:
"I am not overly confident after England's performance against Italy. Quite simply I believe Wales will win the match, but England will still win the title.
Former Wales captain Michael Owen:
"It is a 50/50 game, but with home advantage and a little bit of extra pedigree, I give Wales a slight advantage. I think it is going to be an amazing physical contest. I am not sure it is going to be a great game of rugby, but it is going to be a great finish to the Six Nations."
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