R4 cards are the devil in cartridge size, in the eyes of Nintendo and many developers. Yet despite being banned in Japan over three years ago, Japanese gamers could still quite easily get their hands on one of these pesky cards.

That is until just recently, when the Japanese Ministry of Economy, Trade and Industry stepped in and bought a ban on the import of R4 cartridges. 

R4 cartridges were originally developed to play homebrew apps and software but quickly transformed into a popular way to download and play DS games illegally. 

If you're caught importing one now you could face a prison sentence, so Japanese gamers may want to think twice before trying to swipe a free version of Petz: Hamster Life 2.