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>make a game that takes place in XIX century
It's set in the mid-1900's though. The fact the hokkaido governmental buildings expy is faced in red brick puts it after 1888 (when the real world building was rebuilt with red bricks after being damaged in a previous fire) and the camera model in the photo's shop is more like cameras made at the turn of the 20th century, rather than ones made between 1850-1899.
There's ALSO the meta trivia of the original pokéball creation lore being set in 1925, after the discovery of the ability of pokémon to shrink down and Laventon in L: A stating the invention of the pokéball happened a few years prior to Lucas being sent back in time to join the Galaxy expedition.