Here's how it works: Each sudoku puzzle is a grid of 81 squares—9 squares across and 9 squares down. Within that grid there are 9 larger squares of 3 squares across by 3 squares down. The borders of these larger squares are denoted by thick lines. The object of the game is to fill in the digits 1 through 9 in every column, every row, and every one of the 9 larger squares, without repeating a digit. Each puzzle has some numbers already filled in to get you started.