Both the Nintendo 3DS and the Wii U had a quite slow initial performance in Japan, but the causes may not be entirely Nintendo's responsibility, as explained in an interview to a company's executive on the August issue of the Japanese monthly magazine SAPIO published by Shogakukan, and reported by Yahoo Japan News.

We launched the Nintendo 3DS on February 2011 and sales were strong. Two weeks later we were hit by the Great East Japan Earthquake (Editor's note: that's how the Japanese call the 2011 Tohoku Earthquake) and that stopped the momentum. In August of the same year we lowered the price from the initial 25,000 Yen to 15,000 Yen, and enhanced software development at the same time, to enrich the game line-up.

That paid off and we regained momentum in Japan, but due to that we could not spare many developers for the Wii U (released in November 2012), and that led to the slow start of the console.

While I'm not quite sure the initial performance of the 3DS and the Wii U in Japan is entirely due to the Tohoku Earthquake, it's absolutely true that the natural disaster put the nation on its knees. Even Square Enix had to shut down the Final Fantasy XI and Final Fantasy XIV servers for a while to save energy.

Since then the 3DS definitely recovered, and the Wii U is now showing signs of life with a few solid games in the pipeline. Hopefully the trend will continue.