I'd go for the following side against Japan
01 Nicky Smith
02 Dewi Lake
03 Kieron Assiratti
04 Rhys Davies
05 Adam Beard
06 Taine Plumtree
07 Harri Deaves
08 Aaron Wainwright
09 Tomos Williams
10 Dan Edwards
11 Blair Murray
12 Joe Hawkins
13 Max Llewellyn
14 LRZ
15 Jacob Beetham
16 Brodie Coughlan
17 Rhys Carre
18 Archie Griffin
19 James Fender
20 Morgan Morse
21 RMW
22 Jarrod Evans
23 Louie Hennessey
It's one of Beard or Jenkins for me. Neither are physical enough to play at the same time, and I worry Jenkins has really lost his way both for Wales and Exeter. Ideally I'd dump Beard too, but maybe I'd keep him for his experience for this one.
Bring Deaves straight into start, the lads all heart and aggression, with a good dose of skill to boot. I'd also bring Plumtree in at 6 for his extra physicality, but admit he and Deaves could be a penalty conceding issue waiting to happen.
Hawkins in at 12, and mix up the back 3, bringing Beetham's size in at fullback to bolster the aerial game. I considered dropping Murray entirely, but would like to see him on the wing where he can be slightly less exposed.
I'm not 100% myself with the bench, but I've opted to give some opportunities to Coughlan, Fender, Morse, and Hennessey - I also think they can bring genuine impact that alternatives lack. I'd be happy with either Evans or Sheedy at 22.