The Times Puzzle Books - The Times Kakuro Book 1: 200 Mathematical Logic PuzzlesKakuro originated in the United States in the 1950s under the name of Cross Sums. A logic puzzle, the aim is to complete a grid using digits from 1 to 9, with the digits in each row column adding up to the clue for that block. Its similar to Su Doku in the sense that digits cannot be repeated in a row column. Also known as: Croco Puzzle, Cross Sums, CrossSam, Kasan Kurosu, Kreuzsummenrtsel,Tashizan Cross, Zahlenschwede Are you up to the challenge?