This pocket-sized game has more than 100,000 puzzles. Players simply fill in the grid so that every row, column and 3 x 3 box contains the number 1 through 9. With both beginner and advanced modes, anyone can learn to master the ultimate logic puzzle. In beginner mode the game will flash if the wrong number is put into a cell, and players can save unfinished games. One CR-2032 battery is included.