The 27-year-old Kitahara will start in the number 10 jersey as part of a halfback pairing with co-captain Naoto Saito.
The rest of the backline features Samisoni Tua and Dylan Riley in the centres, wings Inoke Burua and Kippei Ishida, and fullback Kazuma Ueda.
Mamoru Harada packs down at hooker with props Yota Kamimori and Shuhei Takeuchi either side of him, while Harry Hockings and co-captain Warner Dearns make up the second row.
Jack Cornelsen is at number eight in a loose trio with Ben Gunter and Kanji Shimokawa.
Japan also face England on November 14 and travel to Edinburgh to meet Scotland a week later.
Nations Championship 2026
The inaugural Nations Championship will see six northern hemisphere and six southern hemisphere nations battle it out across six rounds in the July and November international windows before assembling in Twickenham for one unforgettable finals weekend on November 27-29.
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Japan team:
Starters: 15-Kazuma Ueda, 14-Kippei Ishida, 13-Dylan Riley, 12-Samisoni Tua, 11-Inoke Burua, 10-Riku Kitahara, 9-Naoto Saito (co-captain), 8-Jack Cornelsen, 7-Kanji Shimokawa, 6-Ben Gunter, 5-Warner Dearns (co-captain), 4-Harry Hockings, 3-Shuhei Takeuchi, 2-Mamoru Harada, 1-Yota Kamimori
Replacements: 16-Kenji Sato, 17-Sojiro Otsuka, 18-Opeti Helu, 19-Michael Stolberg, 20-Tiennan Costley, 21-Kenta Fukuda, 22-Shinya Komura, 23-Jisu Lee
Wales team:
Starters: 15-Blair Murray, 14-Louis Rees-Zammit, 13-Eddie James, 12-Max Llewellyn, 11-Josh Adams, 10-Sam Costelow, 9-Tomos Williams, 8-Aaron Wainwright, 7-Jac Morgan, 6-Alex Mann, 5-Ben Carter, 4-Dafydd Jenkins, 3-Archie Griffin, 2-Dewi Lake (captain), 1-Nicky Smith
Replacements: 16-Ryan Elias, 17-Rhys Carre, 18-Tomas Francis, 19-Teddy Williams, 20-James Botham, 21-Reuben Morgan-Williams, 22-Dan Edwards, 23-Louie Hennessey