The new laws take the force out of the initial impact; the trials to date estimate that the force of the impact is reduced by about 25 per cent by having a pre-bind - the four respective props grabbing each other under the armpits.
By removing the explosiveness of the initial hit, the advantages are many. There is significant evidence that says it will greatly reduce the number of collapses. It should cut down on technical infringements that lead to free kicks and penalties - giving the game more flow.
Then there is the safety aspect; it seems more by good luck than by good management that there aren't more serious spinal injuries in the professional game. Those explosive collisions at the point of engagement often lead to an immediate collapse and can't be good for the players.
"It doesn't take away power - it takes away force," says All Black forwards coach and scrummaging guru Mike Cron who was part of the IRB steering committee that came up with the new procedure. "I would be loath to see the power being taken away but what this should do, if anything, is allow more power to be going through the scrums."
The extent of the experimentation leading to this trial was vast. Cron says endless formats were looked at and monitored - such as not having No 8s attached and using Golden Oldie rules to build an accurate data base of intelligence. He wouldn't have agreed to anything that left the scrum impotent, having worked since 2004 to strengthen the nation's scrummaging expertise both with the All Blacks and working extensively with Super Rugby sides.
He, like many other scrum coaches, is confident both packs will be able to lock into the engagement square. They will be steady and poised before the ball is fed in. The halfbacks will be asked, to feed the ball down the middle and the battle will be about the technical efficiency and power of the respective packs.
At the moment, much of the battle is decided at the initial collision; if one of the tightheads doesn't engage in a position of strength, the scrum is likely to collapse either naturally or deliberately. Under the new sequence, it will be eight versus eight - a straight contest to see which pack can drive the other backwards.
Cron believed not much will change in regard to how the All Blacks and other teams select props.
"No, I don't think so," he says. "It might be that some players really benefit from the change. I wouldn't say that will be generic though it is more likely to be case-specific."