Dr. Kawashima's Brain Training: How Old Is Your Brain?
Dr. Kawashima's Brain Training: How Old Is Your Brain? uses educational puzzles that are math, word games, memorization games, and other kinds of games. The point of the game is to keep the player's brain young using these educational puzzles. The player is supposed to try and keep their brain at 20, which the game says is the perfect age. It's based on a book by Ryuta Kawashima. The DS is held like a book on its side with the top screen on the left and the bottom screen on the right (opposite for lefties).