Description: The aim of the puzzle is to enter a numeral from 1 through 9 in each cell of a grid, most frequently a 9x9 grid made up of 3x3 subgrids (called "regions"), starting with various numerals given in some cells (the "givens"). Each row, column and region must contain only one instance of each numeral. Completing the puzzle requires patience and logical ability. See more instructions in the game