If you're a fan of Sudoku, you and your family will love this colorful alternative. Instead of using numbers to solve the puzzles, Colorku uses brightly colored wooden balls. The gameboard-crafted of solid wood-includes 81 balls in 9 different colors, 104 puzzle cards, solutions booklet, color conversion card and storage tray. There are 5 levels of difficulty. Place it on the coffee table and you're ready whenever you feel like a challenge. Also makes a decorative art piece. What is Sudoku? It is a logic-based number placement puzzle. The object of the game is to fill a 9x9 grid with a number so that every row and column have a number from 1-9 with no repeats and each 3x3 grid has a number from 1-9 with no repeats. The puzzles start with a partially completed grid and the players must fill in the rest.