It’s easy to say that a lot of the success of Nintendo DS (and DS Lite) can be credited to one major title, Brain Age. In only 15 months, the game managed to sell over 4 million copies worldwide, 3 million in Japan, 600k in USA and 500k on Europe.

Brain Age consists of a series of mini games, puzzles, and questions, designed to exercise your brain on a daily basis. Nintendo says that a vast majority of people who buy Brain Age are seniors, looking for a way of keeping the mind sharp. Besides playing cards and bingo.

Nintendo’s press release