Bowing to a request from Nintendo, the government of Japan has outlawed sales of the R4 flash cart, reports PocketGamer:
Among other uses - some of which are legitimate - the R4 allows the playing of pirated games on the Nintendo DS handheld:
To be fair to Nintendo, one of the most prominent uses of DS flash carts is indeed piracy, though such a ham-fisted pursuit of a device that's also used to unlock the console's potential won't do it any favours in the technophile arena.
And right now, cutting off a passionate hardware customer base (on the dawn of a new system release) isn't a particularly wise move for a games system that, it has to be said, is wilting in the sun of a changing industry.
We'll have to wait and see how this Japanese ruling affects the rest of the world, but for the time being Japanese DS gamers are going to have to look elsewhere for their homebrew DS apps.