Before I start to shiny hunt : I've got shiny genned Ditto from wonder trade. Game says ''it's Japanese'' ,but hacker who send me this genned ditto ,is from America . Sooo...it is still compatible with Masuda method? I want legal shines, I never use genned shines to battling
It depends on the language of the Pokémon. If you check the summary of the Pokémon there should be a sign where is says JPN or at least the name should be in Japanese as an indicator of if the Pokémon is Japanese or not.
If the Pokémon is from another language than the one of the game save file you are using, then it’ll work for the Masuda method.