KAKURO is a logic puzzle with simple rules and challenging solutions. Each cell can contain numbers from 1 through 9 The clues in the black cells tells the sum of the numbers next to that clue. (on the right or down) The numbers in consecutive white cells must be unique. The basics are simple: just fill in the empty squares using numbers from 1 to 9 so that the sum of each horizontal set of squares equals the clue on its left, and the sum of each vertical set of squares equals the clue on the top. No number can appear more than once in any sum.