Level-5 working on Professor Layton 6

Level-5 has already started work on a sixth Professor Layton game, CEO Akihiro Hino has revealed.
But his tweet, translated by andriasang, didn't mention a platform.
Four Professor Layton games have been released on DS: Curious Village, Pandora's box, Lost Future and Specter's Flute.
But the most recent Professor Layton game, Mask of Miracle, was a Japanese 3DS launch title.
Will Level-5 opt to stick with the new Nintendo technology?
Earlier this year, Level-5 announced that the four DS Professor Layton games had shipped 11 million copies worldwide between them. Professor Layton and the Miracle Mask has sold nearly 250,000 copies in Japan to date, according to Media Create figures.
Professor Layton and the Lost Future - the most recent European release - triumphed on Eurogamer, earning a gargantuan 9/10 from reviewer John Teti.
Professor Layton games released:

• Professor Layton and the Curious Village - Japan 2007, Europe 2008
• Professor Layton and Pandora's Box - Japan 2009 (Diabolical Box), Europe 2009
• Professor Layton and the Lost Future - Japan 2008 (Unwound Future), Europe 2010
• Professor Layton and the Specter's Flute - Japan 2009, Europe TBC
• Professor Layton and the Mask of Miracle - February 2011, Japan - Europe TBC