Kakuro is a puzzle game logic best described as number-crosswords. Using pure logic and simple subtract calculations, these fascinating puzzles offer endless fun and intellectual entertainment to puzzle fans of all skills and ages. Each problem consists of a blank grid with sum-clues in various places. The object is to fill all empty squares using numbers 1 to 9. So the sum of each horizontal block equals the clue on its left, and the amount of each vertical block equals the evidence on its top. Also, no number may be used in the same block more than once