>>46999124>Meiji/Taishō eraDoubtful. Game Freak isn't touching a sensitive era of Japanese history which may stoke issues with China. (even if those troubles came just a little later) Besides, what exactly is so clear about the Meji Restoration period being the focus?
Considering how ancient Sinnoh myth seems to be, it can be as far back as the Ainu period for all we know, admittedly their clothing seems to be more "modern" than that particular period, though.
Samurott as a starter would indicate something older as well, as the warrior class got phased out in the modernization years of the Meji, and this game will likely not be featuring such focusing on lore. The Sengoku period or Warring States era would be just as fitting for Legends, if not even more so than Edo.
