For a long time Kakuro was the most popular logic-game in Japan, prior to the entrance of Sudoku. With Kakuro, the players develop their problem solving skills. Kakuro compares to a crossword puzzle, where the letters have been replaced by digits, but Kakuro has a greater dimension than the multiplication table.
There is a 6 x 6 and a 9 x 9 cell grid in the Kakuro Puzzle and both can be played in 5 difficulty levels. The goal is to use the numbers from 1 to 9 so that the sum of both the horizontal and the vertical columns equal the given amounts.
Kakuro is available in easy and expert versions.