Rugby World Cup 2015: The All Blacks' big weakness

New Zealand All Blacks assistant coach Ian Foster talks with 2nd-five Sonny Bill Williams, after a team training session, held at their training ground. Photo / Brett Phibbs.

As predicted, it has been a World Cup tailor made for loose forwards. The breakdown has been the key battleground and the stars to date have been the likes of David Pocock, Michael Hooper and Sean O'Brien.

Win that contest over the ball and win the game. That's where Australia effectively killed England and where Ireland had it all over France.

New Zealand, so far, haven't appeared to be operating in this area with the same intensity, accuracy or success.

If the statistics are to be believed, they are off the pace. The breakdown hasn't been a strength for them at this tournament - or so the picture would look.

They have won an average of eight turnovers per game which is in line or better than most of the other teams left. But they have conceded an average of 20 turnovers per game which is easily the highest.

For those looking for reasons to condemn the All Blacks, this is another stick with which they can seemingly be beaten.

A number like that poses a few questions, none more pertinent than whether they are committing enough numbers to the breakdown.

The All Blacks have built their attacking plan on their ability to recycle with fewer numbers than the opposition. If the opposition send in three to compete for the ball, the All Blacks will back themselves to secure possession with two.

It leaves them with a man advantage in the outfield and a chance to create and exploit space.

It's also reasonable to ask whether the All Blacks are getting to the ball carrier quickly enough. Is age catching up with some players?

Reasonable to ask and reasonable to assume that the All Blacks will be aware of their need to be over the tackled player more quickly against France and more ruthless and accurate at the cleanout.

But there are other factors that have distorted a picture which may not be as real or as gloomy as the numbers suggest.

There is a natural correlation between metres gained and turnovers conceded - the more teams run with the ball, the more likely it is they will be isolated and turned over. The All Blacks barely used their kicking game against Namibia, Georgia and Tonga. They ran from everywhere - which was higher risk but of course higher reward, too as ball in hand rugby creates opportunity.

Against France they will kick more: a lot more but what's also been apparent in the pool rounds is that the All Blacks weren't competing much at the breakdown. They have been skinning the cat a different way as it were.

They have talked about having a particular focus and in their last three games, that has been about using their defence as a weapon.

"We can vary how we like to defend," says Sam Cane. "You will have seen a lot in the pool play that we are jot contesting rucks a lot but we are putting teams under pressure with our linespeed and physicality that way - forcing teams into errors and trying to cut down their time and space.

"We can change tactics as we obviously have guys who are good on the pill as well it is just depending on the opposition we are playing as to how often we try to to contest the breakdown."

The wider picture shows that the All Blacks lead the competition on nearly every defensive measurement. Their average number of missed tackles per game is 10.5; teams on average only make 190m against them carrying the ball; they have only been allowed to make an average of 84 carries and 91 passes.

Australia and Ireland have only conceded an average of 8.8 points per game, but New Zealand are next on 12 and that number is higher largely because their opposition on average have kicked 94 per cent of their goals when playing the All Blacks.

The breakdown battle isn't strictly determined by the number of turnovers won and lost. Pressure can be exerted through different means.