There is enough at stake at Twickenham on Sunday for England and Wales not to focus on what implications victory or defeat would carry ahead of next year's World Cup when the teams will meet in the pool stage, but as Warren Gatland acknowledged this week, there will be a ghost at the door of both dressing rooms.
It is arguable that defeat would carry more significance for Wales than it would for England given the continuity in selection they have enjoyed since the last World Cup. Last month's comprehensive defeat to Ireland in Dublin forced their head coach to issue a warning to his senior players that a repeat would see some of them dropped from the squad.
He got the response he wanted against France in the last round, but England at Twickenham will ask far more searching questions of them than Philippe Saint-André's team which, despite a winning start, continues to wander around in circles. Wales struggled to deal with the unexpected in Dublin and England have this season shown they have the capacity to surprise.
A defeat of Dublin proportions would leave Gatland in the position he found himself at the end of the 2010 Six Nations, when Wales lost three of their five matches. He promoted young forwards like Sam Warburton, who started the final match against Italy that year, and Toby Faletau: experienced players, such as Martyn Williams, Lee Byrne, Ian Gough, Jonathan Thomas and Ian Gough were phased out, some gradually.
Eleven of Wales's starting lineup against France in the 2011 World Cup semi-final will take the field at Twickenham. In comparison, England may not field any of the team that played against France in their final match of that tournament: Manu Tuilagi, available again for selection in the centre but not considered match-fit, was the one possibility with Dan Cole and Tom Croft injured.
The England head coach, Stuart Lancaster, has produced a new side from the ruins of that campaign and two more players who took part in it, Chris Ashton and Ben Youngs, have been overlooked this Six Nations. Gatland is a coach who relies on evidence rather than sentiment and the continued omission of the scrum-half Mike Phillips is an indication that performance, in matches and in training, is what counts.
Wales follow the Six Nations with a tour to South Africa, and they play all three major southern hemisphere teams in the autumn, supplemented by a fixture with Fiji. If England outplay them, Gatland would have to consider blooding players against the top teams in the world and he has yet to find replacements in kind for the props Gethin Jenkins and Adam Jones, although the Scarlets tighthead Samson Lee has been making an impact in the Pro12.
Wales have a settled combination behind, but while Lancaster has, because of injuries, built virtually two distinct back divisions (outside-half is his one concern with Toby Flood exiled due to his impending move to France and Freddie Burns out of form), Gatland is struggling to cover Leigh Halfpenny at full-back, Jamie Roberts at inside-centre and George North on the left-wing.
Gatland's approach remains overtly physical: James Hook, a marginal figure in the last couple of seasons, has been dropped from the bench. His instinct and feel for the game are out of sync with the deliberate, direct style of the side, but while Wales have been successful in Europe in recent years their last victory over a major southern hemisphere side was back in 2008.
Australia are in Wales's World Cup group and history would suggest Gatland's men are more likely to defeat England than the Wallabies, who in Cardiff last November stood up to the physical onslaught from their hosts and won the game with enterprising back play orchestrated by Quade Cooper.
A worry for Wales is that England are developing not only options behind the scrum but an ability to break defences without relying on brute force. In four matches this season, against Australia, New Zealand, France and Ireland, they have turned a deficit of at least seven points into a lead (double figures in the cases of the All Blacks and Les Bleus): they only held on twice, but each time they responded with tries rather than penalties kicked by Owen Farrell.
If defeat for Wales on Sunday would prompt a rethink for Gatland, in terms of personnel rather than style, the impact for England would be more psychological. They have lost their last three matches against Wales, two in the Six Nations, and have not scored a try in any of them. Failure to win in Cardiff next year would mean going into the World Cup not having beaten the men in red since before the start of the previous tournament.
Lancaster, though, would not have to dismantle. He has players such as Tuilagi, Croft, Alex Corbisiero, Cole, Marland Yarde and Christian Wade to return. He has been building while Gatland has been focused on maintenance and adding an extension. The two teams will meet at Twickenham in different phases of development and Wales, after the defeats to Australia and Ireland, would need to re-evaluate just a month after Gatland told his players to think and act like champions.
With four regions to draw his players from, as opposed to 12 clubs, Gatland has a shallower pool than Lancaster. Wales need momentum, but just as his options in terms of personnel are limited, so Wales's playing style has remained constant in his six years at the helm. The former Australia full-back Greg Martin coined the term Warrenball before last year's Lions series: it was not intended to be pejorative but a reflection on how various teams under him have played.
Gatland breeds physical and mental hardness in which conditioning plays an integral part. Before him, Wales were maddeningly inconsistent, highs and lows, but they have developed a constancy. It leaves them vulnerable to teams who are able to raise their game a few notches, as they found in Dublin last month, and while Ireland tried to confound England with the unexpected in the last round, Wales will look to dominate physically.
Gatland is not likely to change a strategy that has worked so well for him but refine it. Only one team have beaten Wales in the Six Nations since the last World Cup and if they have a stronger team than England, it is Lancaster who looks to have developed the stronger squad and be better insured against injuries – and defeat on Sunday.
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