It's Sudoku but with colour. The game comes with a wood board with a 9 x 9 grid, 81 marbles, nine each of nine beautiful bright colors, and 104 puzzle cards in 5 levels of difficulty. The game is similar to Sudoku but you use one of the 104 challenging cards to lay out the board and then you must solve the placement of the colored balls so that no two colors are in the same column, row, or 3 x 3 square. A great game to play by your self or with others. Unlike Sudoku, Colorku can be played in Teams. Also, the board can be used to solve ANY sudoku puzzle, by easily converting numbers to colors. It's a great way to help younger children learn deductive reasoning and logic. It's also a great way for anyone to keep their mind sharp! Helps to bring the right and left side of the brain working together.