The basic Sudoku game, is a printed grid of 9 rows and 9 columns making 81 spaces, sub divided into 9 "regions" of 9 spaces. Each line, both horizontally (rows) and vertically (columns) as well as the regions (boxes of 9 spaces) MUST have one of each and only one of each number from 1 through 9 in ANY order for the finished puzzle.
The opening puzzle has about 20 to 38 of the 81 spaces filled in with number "clues". The player must deduct based upon logic the numbers that belong in the remaining spaces.
There is ONLY ONE correct solution to each puzzle.
The answer must be determined based upon logic and deduction rather than luck or guessing. Unless certain, a player should not fill in a guess because if wrong, it will throw the entire game out of whack making it almost impossible to complete.