WHEN you scout an opponent, you'll come up with a few ways to attack them in areas where they might be weak.
The teams that don't know their areas of weakness are the easiest ones to exploit, while the teams that manage any glaring weaknesses with a change in their defensive (or attacking) structure are trickier to move into positions where you can isolate and then attack that weakness.
My understanding of this concept was explained to me in New Zealand on an exaggerated scale.
"If you want to know what a structural weakness is," my coach told me, "you have to imagine how you'd exploit the opposition if they had a 10-year-old boy lining out for them, be it in the front row, the back row, at halfback, or further out. Boil everything down from there."
That's what clicked it for me.
If they had a 10-year-old boy defending the wing but didn't know it, what would you look to target him? You'd kick contestable balls at him.
You'd also widen your attack to get your winger one on one with him as often as possible.
If the 10-year-old boy was playing at hooker what would you do? You'd get your tighthead to drive in at him on every scrum and throw a jumper up at the front of all his throws.
If they had a 10-year-old playing at 12, you'd structure moves off your set piece to isolate him one on one with one of your big runners until the opposition narrowed on him to protect him and then you'd target the spaces they left behind elsewhere in doing so.
Finding that "10-year-old" in the opposition can vary from team to team. Poor sides have multiple avenues of attack and all you have to do is pick one or two with the rest as backups.
Better sides might only have a specific weakness that you can only exploit in certain positions.
Either way, you need to execute your plan with accuracy to ensure you hit the weakness head-on. In the December back to backs, that need to exploit weakness is vital.
Castres, as I went over last week, have one major weakness in their set up and that's their lateral speed on defensive sets, be it multiphase or on set piece.
The conditions and late injury changes didn't really allow Munster to pressurise that lateral speed (and subsequent rushed decision making) on phase play until late in the second half.
CJ Stander’s try was a good example. Munster went across the field setting four quick ruck points as they went. The Castres forwards moved incredibly slowly across the middle of the pitch as they move to all three defensive fold points.
By the time the ball reaches the end of the line with Sam Arnold, there was massive amounts of space at the ABC defensive position from the ruck pillar on out.
Samson, a replacement lock, was defending 10m of lateral space all on his own with Babillot and Caballero compacted as B and C defenders.
Murray slid across the gap and put Stander away through a colossal hole after Babillot and Caballero doubled up on Holland.
But that space could only be exploited because Castres didn't have the numbers to properly stack their defence from the ruck pillar on out.
They lagged behind from the previous rucks and that created an opportunity for Murray to attack a weakness he'll have looked at pre-game.
A lot of Munster’s early lineouts looked like overthrows but I don't think they were. I think the intention was to compress Castres as much as possible by tempting them into counter-launches (four men lifting two jumpers) and then using the ball in the wide area to get a look at attacking Castres lineout tail gunners.
A lot of Munster's work in the first half from the lineout was designed to attack the seam between the last forwards - usually Tulou or Jenneker - and the fly-half Benjamin Urdipilleta.
Munster used a maul feint - where the pack compressed into a maul formation before breaking away quickly - to attack Castres lack of lateral speed over the ground.
Chris Cloete was the main guy Munster used in this play, he’s extremely quick and agile so, it seemed to me that they wanted to give Cloete as much of a chance as possible to expose Jenneker, the Castres hooker, in space as the rest of the Castres pack piled in for a maul.
Munster almost scored from this play - when Conway punched through a gap but just missed an offload to Scannell - but I’d expect to see Munster go after that again this weekend.
The back to back games in December give the coaches and video analysts a unique opportunity to tweak what went wrong in the previous game against the same opposition.
Castres won’t have much to work with because they played so little rugby so when it comes to what will work, they can only go on what they had stored up for this game.
Munster, on the other hand, will have a tonne of footage to show where and how they went wrong in Thomond Park and come up with a plan to hit Castres where it hurts and take full control of this pool.