Perhaps the most eagerly anticipated decision was at fly-half where Scarlets’ Rhys Patchell got the nod over Jarrod Evans, but there were plenty more selections that stood out.
With that in mind, we have taken a detailed look at some of the biggest decisions and what they mean for Japan.
KEYS TO NO.10
We have to start at fly-half where Gareth Anscombe’s injury left Gatland with a big decision to make. First, he had to decide whether he was going to take two fly-halves or three, and if it was the former, who would get the nod.
In the end Gatland has gone with two, knowing that Hadleigh Parkes can fill in at ten in an emergency, having done so in the past for the Scarlets.
From there it looked like Evans might be next in line, given the chance to start against Ireland on Saturday, but Patchell’s performance off the bench apparently did enough to get him in.
Although he missed out initially, Evans will be next in line if anything were to happen to either of the two fly-halves selected, Patchell and Dan Biggar.
If Patchell’s call-up was not a huge shock considering his display the previous day, the front row calls were somewhat more surprising.
Rob Evans has been a stalwart of the Welsh pack for a number of years, but saw his place taken by youngster Rhys Carré, who came through the ranks at Cardiff Blues before joining Saracens this summer.
Carré is one of three loosehead props, alongside Nicky Smith and Wyn Jones, with the latter also set to serve as tighthead cover with just two specialists included.
Those are Tomas Francis and Dillon Lewis, as Samson Lee was another to miss out in the final shakeup.
Considering Jones’ lack of experience at tighthead, Lee seems the most likely call-up in the front row if someone does go down.
FAITH IN HILL
In the second row Gatland has relied for the most part on Alun Wyn Jones, Adam Beard and Cory Hill over the last 18 months, and he clearly had a lot of faith in the Dragons lock.
He has not featured since scoring a crucial try against England in the Guinness Six Nations because of a stress fracture in his leg.
Hill will not be ready for the first group game, but Gatland was clearly desperate to keep him in the squad, aided by Aaron Shingler’s ability to fill in at lock at a push.
Shingler is one of six back-rowers in the squad, with Ross Moriarty, Aaron Wainwright, Josh Navidi and Justin Tipuric all involved again after playing extensive roles in the Grand Slam.
The one other player who did not feature in the spring was James Davies, with the Scarlets flanker doing enough over the last two games against England and Ireland to get selected.
Considering that Gatland has gone with an 18-13 split between forwards and backs, Davies’ ability to fill in on the wing, as he did in a Guinness PRO14 final, could yet come in handy.
The unlucky nine who missed out on selection were Rob Evans, Samson Lee, Leon Brown, Bradley Davies, Jarrod Evans, Scott Williams, Owen Lane, Jonah Holmes and Steff Evans.
Of those, Lee, Davies, Jarrod Evans and Scott Williams feel the most likely to receive a call-up, simply because of the lack of cover in those positions.
Gatland knew he was going to have some tough decisions to make, as ever, he was not afraid to make them.
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