Nintendo's 3DS units in Japan, only about half have been sold.
According to this article (if you can read Japanese), when the 3DS was released, Nintendo claimed that 1.5 million of the 4 million handhelds were heading to Japan by the end of March. According to Japanese sales trackers like Media Create, there are a ton of unsold units in Japan. The sales trackerreports that only 836,000 3DS units have been sold, meaning Nintendo hasn't hit the one million mark in Japan. About 664,000 units from released are still waiting to be purchased.
There are many probable reasons for this. The Earthquake is one of them. However the earthquake did have a bit of effect on the sales for the western side of Japan (which wasn't effected by the natural disaster). Other reasons could be the unfortunate timing for Nintendo and their poor decisions such as a lack of launch titles.
Meanwhile the 3DS is competing with the PSP from Sony, and 3DS units are being sold as used in shops around the country.
While this seems like some unfortunate news for Nintendo, they aren't giving up. While the struggle to be number 1 in portable gaming consoles continues, they will probably grow their numbers when more titles are released. Only time will tell.