While there’s already a number of homebrew solutions that accomplish the same thing, Nintendo is finally seeing its way to providing an official tool that extracts saves from cartridges and places them on the device’s SD card. The tool is meant to free saves for use with downloadable eShop versions of cartridge games.
The tool is only seeing release in Japan at the moment with no news of release in other territories, but with the growing number of eShop releases and one less reason for players to resort to not exactly legal homebrew solutions, it shouldn’t be too long before this makes it to Western shores. Nintendogs + Cats, Fire Emblem: Awakening, Pokémon Rumble Blast, Culdcept, and Pocket Soccer League Calcio Bit are all joining the Japanese eShop line-up at month’s end and will benefit from the save transfer tool.
Source Nintendo World Report