Based on recent history, two things are certain when the Chiefs meet the Blues tonight - there will be 80 minutes of vicious collisions and, in the end, the Chiefs will win.
That much appears preordained ahead of tonight's clash at Eden Park, supported by evidence gleaned from a glut of New Zealand derbies and, in particular, clashes between these teams.
First, the attrition rate these matches take on conference foes has been clear all season and was re-emphasised in the Chiefs' loss to the Crusaders last weekend, with three players forced from the field through concussion.
And with regards to the final result, one compelling statistic seems to suggest it's a done deal - the Chiefs have emerged triumphant from the past 11 meetings between the northern neighbours.
Faced with those two patterns, though, a deferential Dave Rennie would express his confidence in only one continuing.