According to Japanese gaming website Game.Watch.Impress the Japanese version of Yakuza: Like a Dragon on Xbox ([sic] not Ryu Ga Gotoku 7 but the English version with all of the Series X upgrades) was never officially announced to be launched in its own home country.
When asked for comment SEGA stated “The release of the Xbox Series X version of” Yakuza: Like a Dragon “in Japan has not been officially announced by us.”
So it seems the Xbox x SEGA partnership may not be extending to Japan making the launch of the new consoles even more lite than they already appear. Strangely at the time of publication the Japanese version of Yakuza: like a Dragon is still available for preorder on the Japanese Xbox store but it’s unclear what this means for Japanese fans looking to grab it at launch.
Update: The title has now been removed from the Japanese Xbox store for preorder