Nintendo has revealed that 3DS games aimed at adult or mature markets will have slightly different packaging to other titles in Japan.
The first game to carry the change will be Ubisoft's Splinter Cell 3D, the spine of which will be black. Most DS games have a white spine on the sleeve.
Kotaku notes that Nintendo started doing the same with Wii games last year in the territory.
To date Nintendo has not introduced such a colour scheme in other territories.