I already own a copy of both black and white, and me and a friend are doing a playthrough together. Was wondering if buying another copy of the game, would that count as a new save file? Or would both copies boot up the same save file? I own 3Ds XL's. I wanted to have a separate playthrough for a shiny only run.
Prior to LGPE, save data is stored to the cartridge, not the console. This means that any individual cartridge of Black/White will start a unique save file, even if inserted into a DS that has already played a different cartridge of Black/White.