How good are you at Sudoku? You can find out on this time based version without turning over an hour glass. If you have not played Sudoku before, you must be start playing. Its very simple and highly addictive. Place the numbers 1 to 9 in the grids so they only appear once in each row, column and 3X3 domain. No mathematics. Just use logic. Sudoku Countdown is Sudoku with a clock counting down your score.