The most popular videogame in Japan is not some crash 'em up, beat 'em up and then steal their money thriller. It's a "Brain Training" game designed to sharpen the mind and keep it fresh. According to Cabel Sasser:you hold your Nintendo DS like a book (with left and right screens), and you basically use the touchscreen to undergo a wide variety of simple, cleanly-designed, interesting exercises intended to make you smarter. Or, at least, keep your brain sharp and fresh and delicious. At the end of your "fun", the game eventually calculates and reports your "mental age"