The R4DS flashcard allows you to play pirated Nintendo DS games, just get your games from somewhere, put it into a microSD card and into the flashcard, and you’re all set to play the games you want.

This is a very massive act of software piracy. Nintendo has always done its best to battle piracy and it has won (on a small scale) because the R4DS flashcard for the Nintendo DS has officially been banned, by court, in Japan. Playing pirated games is not the only feature of the R4DS flashcard, it also enables you to listen to music, watch videos and use homebrew applications.

I say that they only won on a small scale because there are so many variants of this type of flashcard for the Nintendo DS. Even the original makers of the R4DS are having problems of their own because other manufacturers copied their design and then sell it using the same R4DS brand name.

Although the flashcard has already been banned in Japan by court officials, sales of the R4DS flashcard still continues, particularly in Akihabara.

More information elsewhere:

• Nintendo Wins Against R4 in Japan, The Last-ditch Struggle of DS Flashcard (Gameyeeeah)
• Japan Outlaws R4 Cartridge (Digital Battle)
• Nintendo Wins Against R4 in Japan, The Last-ditch Struggle of DS Flashcard (Ishopvideogame Blog)
• Court Injunction Or Not, R4 Devices Still On Sale In Akihabara (Kotaku)