The point of the game is to fill the whole grid with numbers. Numbers you can place are only from 1 up to 9. You will notice that the big grid is 9x9. This board is seperated into 9 smaller boards of 3x3. Within the 3x3 boards all numbers from 1 to 9 must be placed. The same number cannot appear in the same column or in the same row. All numbers from 1 to 9 must appear within each row and each column.