According to Siliconera, Nintendo Japan will be ditching white game cases for any games rated Cero C (15+), D (17+), or Z (18+), and will begin using black boxes for games aimed at an older audience. Beginning with Zangeki no Reginleiv, consumers will instantly be able to tell the age range of the game based solely on the color, as well as being able to use the rating branding on the front of the box.

I'm hoping that this practice makes its way to North America. It's not that I don't like having a consistent look on my shelves, but you can't deny that the black style looks much better than the current white palette Nintendo's using. I mean, look at that box art with the black coloring. It just looks more regal and dignified, doesn't it? I don't know what we'll have to do to convince Nintendo of America to adopt this foreign policy, but I think this is something we all need to start a movement on now. Think about how much cooler the MadWorld or Resident Evil: The Darkside Chronicles box art would have looked.

Yeah, those are pretty cool. Reggie, if you're listening, or reading, know that America wants black Wii boxes just as much as Japan, if not more. If you guys are looking for another factor to help sell Mature rated content on the Wii, nothing will help catch a prospective customer's eye like a different colored box on the shelf.

[Source]