About this game
Sudoku Online
Sudoku Online brings the familiar nine-by-nine number grid together with several rule variations. Start with classic Sudoku and choose from four difficulty settings, then explore X-Sudoku, Windoku, Killer Sudoku or Kropki when you want a different kind of deduction. Each variation changes which clues you must consider, so solving a familiar-looking grid can require a fresh approach.
How to play
Fill each row, column and three-by-three box with the numbers 1–9, without repeats. Start where the supplied clues leave the fewest possibilities and use notes to record candidates. In X-Sudoku, check both main diagonals; in Killer Sudoku, respect each marked group's total. For Kropki, a white dot links consecutive numbers, while a black dot means one number is twice the other. Check these extra conditions before committing to an answer.
