No pencil or paper required for this fun Sudoku puzzle game! Fill each row, column and square with numbers 1 to 9 without repeating them. This testing wooden game is a great way to train the brain from an early age. Includes a handy tray to store all of the numbers whilst they're not in use. A great game to develop the strategic mind. Made from high quality, responsibly sourced materials. Conforms to current European safety standards. Bigjigs is a UK based, family-run business (the Ireland family) which specialises in traditional wooden toys, ethically made from environmentally responsible materials (ie rubberwood, FSC certified wood).