"He makes his debut against Wales and scores a try that he doesn't remember," says Mike Ross of Paul O'Connell, who will pick up his 100th cap against the men from the principality this weekend.

It's the one subject the Ireland squad are not discussing this week in their walks around the estate, the thing O'Connell has not mentioned. It's maybe at the other end of the spectrum from debut. But 100 caps is a lot of dirt in a lock's face.

Players are treading lightly as though bringing it up will deflect from the threat of Wales and personalise a team that has found value in collective spirit. If O’Connell sees his own benchmark this week as the enemy within, it’s not how Ross sees it.

The Ireland tighthead prop boxes him as one of those souls that sees the mighty in the mundane.

Similar to Joe Schmidt, there's greatness in small things. "He was at training this week, questioning me on what bind feels best in a particular scrum," says Ross. As you do.

But O'Connell's 100-cap mark is not the hazard this week, it's Warren Gatland and Wales. There Ireland will play – and O'Connell would approve – with a blend of accuracy and passion.

In a world in which every team can recite each other's play book, it may turn into a game of wills or, with Wayne Barnes refereeing, interpretation. But first Wales.

“As the games go on, it just gets more difficult because teams have more footage of you and they know what to expect,” says Ross. “Wales are strong in a lot of areas. They have good lads in their air and on the ground.

Predictability

“They have some big carriers and a good pack. They’re a team we have a lot of experience with because we meet their players all the time in the Pro12. It will be one of the toughest games of the championship.”

Predictability in a team might be seen at the outset as counter-intuitive. But Wales will bring a sameness that promotes less the idea of easy to work out and more of having a simple system that works. It’s easy to predict the path of the boulder rolling down a hill but try stopping it.

“They do it all the time because they’re bloody good, effective,” says Ross. “You have those big carriers crashing over the gain-line, that wide, wide game they play. It can be pretty exhausting to defend against, especially if they’re getting over the gain-line with heir big runners. You’re kind of scrambling to try to keep the line intact.”

But the scrum is where Ross will be judged and with the combination of Barnes and Gethin Jenkins, it might not be straightforward. The Irish scrum was not an issue against England, a good thing, but with Jenkins it may become more edgy and interpretive.

Ross's surprising admission is that illegal manoeuvres don't generally pay off and through scrum coach Greg Feek they are discouraged.

“He mixes up what he does,” says the Ireland prop of Jenkins. “He’s a very experienced campaigner, Wales’s most capped player ever, yeah? He has 117 caps or something like that so he has a lot of arrows in his armoury.

“He might come across me, he might stay there. It just depends what he’s in the mood for that day.

“You always hope that if you’re keeping a legal shape and your opponent doesn’t, then the ref picks up on that.

“Feeky knocked that out of me a while ago. When I was in Premiership it was a case of anything goes as long as you’re going forward. So the obvious one for a tighthead is to go in across the hooker.

“But if you don’t get that right you’re leaving yourself open for a world of pain. So the percentage move is to stay straight.”

A world apart. Not all understand it. Few more are interested. But some are. And the man with 99 caps is one.