Accenture Analysis: Nick Mallett's take on RBS 6 Nations Round Four Read more at http://www.rbs6nations.com/en/news/29708.php#wTlJOQFS3poAykfX.99
RBS 6 Nations
England and Wales will do battle for the chance to win the title, while Italy and the struggling Irish are both desperate to avoid the wooden spoon.
Never miss RBS 6 Nations fixtures, stats or latest news!
Meanwhile, it will be fascinating to see if Scotland can now overcome France after winning their first RBS 6 Nations game for two years.
England v Wales
In the build-up to this game, I can assure you Warren Gatland and his coaches will be desperately trying to devise a plan to stop Billy Vunipola, because they know if they can achieve that, they will take a huge stride towards winning both this game and the title.
Vunipola has been crucial to England's success so far and for me has been the player of the RBS 6 Nations so far.
He really is immense and his explosive ball carrying skills have created so much space for the England backs to exploit.
The problem for Wales is it will be far from easy to stop Vunipola, simply because he is such a smart player, who plays with great variety. He really is anything but predictable.
He is not a player who just comes around the corner, but rather he will take the ball from another forward, the 9, the 10, as well as dropping deep and taking it from Mike Brown off a kick return.
And when you do get to him, he is just so powerful and always in your face, and crucially picks the right players to run at. He is also incredibly strong around the hips and doesn't go to ground easily.
Wales can do better
Wales want more credit for their unbeaten run so far, but I have to tell you, I don't think they deserve it, and they have been largely underwhelming against Ireland, Scotland and a poor France side.
They will struggle against England as they lack the explosive ball carrying from their forwards compared to their opponents, and even someone like Taulupe Faletau doesn't create the sort of momentum that England's pack can.
Yes, Wales have impressive backs, but there seems to be a missing link between backs and forwards, and so overall they are not producing enough opportunities.
Rugby can be over-complicated, but this is very simple: forwards create and backs finish off, but that is not happening for Wales and the contrast between the two sides' ruck speed shows how much more effective England's ball carriers are in supplying quick ball.
Looking ahead to the clash at Twickenham with the Accenture Analysis Team it was remarkable to discover that England are the most improved side in the RBS 6 Nations when it comes to moving the ball away from the ruck. They were comfortably the slowest of any nation in 2015, but have bucked the trend of a slowing Championship average and are now third fastest behind Ireland and France, shaving an impressive 0.71 seconds off their recycle speed. In contrast, Wales are the slowest after three rounds.
England will need their ball carriers to be at their best and maintain their improved speed of recycling the ball, though, if they are going to cause Wales' impressive defence problems.
This will be a tight game, but I sense England have more incentive to win and their renewed belief under Eddie Jones will be enough to carry them to victory at Twickenham.
Scotland v France
After finally ending their long losing run against Italy in the last round, Scotland will now be confident of securing another win against France, who increasingly appear to be the least well organised side in this year's RBS 6 Nations.
So far I have really struggled to see much logic in the French approach. It looks a real mess, especially after three or four phases, where no one seems quite sure what they are doing.
France's unstructured approach in this year's Championship can be seen in the number of offloads they have made so far, compared to the number of metres made as a result of these offloads. France have made 45 offloads in the opening three rounds whereas all other nations have made just 55 offloads between them. The problem for the French is that they are not building momentum from these offloads, making an average of 2.12 metres from each offload in the first five phases, but then a mere average of 0.75 metres for each offload in their next five phases.
France are an accident waiting to happen, no one seems to know who is passing to who and so they are constantly risking turnovers.
Their saving grace is their defence, which boasts several big and physical players, who remain competitive at the breakdown, but I have a feeling the Scots might still be able to get past them.
Dangerous Scottish backs
In the last round, Scotland prospered as they were able to get outside the Italian defence and their backs were the difference.
The Scots were also able to nullify the Italians at set pieces and were particularly strong in the scrum, once again bolstered by WP Nel. Yes, I know I bang on about him, but the guy is very good!
This is a hard game to call, it seems 50-50 to me, but Scotland have a point to prove and after the win against Italy I think they might just do it.
Ireland v Italy
At the moment, Ireland really do look a pale imitation of the side who won the RBS 6 Nations only a year ago.
They are a team in transition, desperately missing a host of experienced players and having to deal with the reality of a significantly weaker pack.
But what did they expect? You can't lose players like Paul O'Connell through retirement and Sean O'Brien through injury without it impacting your side. Unfortunately for Ireland their replacements have been adequate at best.
Accenture's data shows that Ireland's forwards are not performing at the level set last year with the number of carries, metres made, gain line crosses and metres made beyond the gain line per match decreasing.
The Irish also now lack the set piece stability that allow their backs to boss games like last year when the scrum-half and fly-half had time to kick and pass. They are now under a lot more pressure.
Ireland's kicking game, which was so crucial last year from Connor Murray, appears to have imploded and they have simply lost their basic accuracy, and their ability to retain possession here.
But for all their problems, I would still expect Ireland to have enough to get past the Italians in Dublin this weekend.
Italy's decision to move away from being dominant at set pieces has backfired and only served to undermine them.
They are trying to play with more width, fluidity and movement, but it isn't as effective and their most recent win was actually when they went back to their previous more defensive approach.
You have to play a style of rugby your opposition dislikes and yet Italy are far too accommodating and play right into the opposition's hands. It is time to accept this expansive rugby has not been a success and rediscover those strengths of Italian rugby.
Nick Mallett is part of the Accenture Analysis Team during the RBS 6 Nations, providing fans with insight and analysis to #Seebeyond standard match data. Follow @AccentureRugby, visit accenture-rugby.com or download the Official RBS 6 Nations app.
Read more at http://www.rbs6nations.com/en/news/29708.php#wTlJOQFS3poAykfX.99