The cases for the defences favour Munster's marauders
It couldn't be more finely balanced.
There are ten rounds down in the PRO12 League and Munster lead Leinster by the razor's edge of points-difference.
They have both won eight out of ten and been in rude good health in The Champions Cup.
In the most simple terms, the Irish provinces have assembled the same amount of tries (34) in the League and are really separated by what they have given-up rather than what they have touched down.
Hosts Munster have embraced defence coach Jacques Nienaber's system to leak 15 tries in ten matches.
This makes them the meanest defence in the PRO12 on both counts of tries and points against (129).
Meanwhile, Leinster have not been as miserly in shipping 24 tries.
There is a reasonable explanation.
Stuart Lancaster officially arrived as the like-for-like defence coach for the departed Kurt McQuilkin.
He was late into the club and unable to put in place all the foundations of his platform before the beginning of the season.
The players have had to learn the hard way on the job.
Behind the scenes, the former England coach took on a more complete role.
He has spread himself thinner than Nienaber in putting his experience and organisational strengths into practice.
There have been encouraging signs for Lancaster, especially the manner in which Leinster resisted Northampton's drive for a late try at The Aviva.
It will be interesting to see how the visitors cope with Munster's swarming, suffocating defence.
It could just be made for the educated kicking game of out-half Ross Byrne.