Zangeki no Reginleiv is the first game to get this special treatment.
Starting next month, all games published in Japan by Nintendo that receive a rating of CERO C or above will hit retailers in a special black box designed to warn parents of the mature nature of the title.
The first game to receive this special treatment will be Zangeki no Reginleiv, which is slated for a mid-February release. Reginleiv is also the first Wii game in Japan to receive a retail demo that gamers in the region can rent for free.
These special black boxes are currently only being used by Nintendo of Japan, and there's no word on whether or not Nintendo of America will apply a similar approach to their mature titles.