Nintendo 3DS. The first Bokujou Monogatari game localized by XSeed Games. [ Game Guide ] JP release = Feb 2014. NA release = Mar 2015. EU release = Dec 2015.
Overwrite it with a new game save. I don't think there's any way to delete a file. You just have to overwrite it. Start a new game, and save over File 1 or whichever save you want to get rid of.