Joe Schmidt is blessed when it comes to second-row options and Mike McCarthy thinks it is down to two Munster men for the final spot in the World Cup squad.
Speaking on Friday's OTB AM, the former Leinster man said Ireland is stacked at second-row.
"I think he [Joe Schmidt] will take four second-rows but as I mentioned last time about the strength in depth we got since 2015.
"When you look at some of the guys that aren't going: Ultan Dillane, Quinn Roux, Gavin Thornbury and Ross Moloney.
"I think he will take four but the big talking point is who will go between Tadhg Beirne and Jean Kleyn?" McCarthy said.
He had some very interesting points about how each player could be utilised in the squad.
"If it is a pool stage game I would like to see Tadhg Beirne coming off the bench and doing what he did against Italy. He got two turnovers in virtually 60 seconds.
"If it's a quarter-final against South Africa maybe I would like to see Jean Kleyn starting.
"In the Six Nations maybe one area we lacked for those games against Wales and England was a bit of physicality.
"We weren't winning the collisions and he's a guy who can completely change that," the former Ireland international said.
When it comes to the other three players, McCarthy was fairly clear on who should be going to Japan.
"James Ryan is like the terminator the amount of work he gets through with the tackles and carries getting over the gain line and winning those inches.
"Henderson is dead set with what he has achieved and he's obviously leadership material now that he's captaining Ulster.
"With Dev [Toner] we've seen what happens when he doesn't play, he's the set-piece foundation.
"One of the things people probably don't see is the unseen work that he does that has a ripple effect on the team," he said.