Play Kropki Sudoku Online Free

Play Kropki Sudoku online for free. Black and white dots between cells indicate ratio and consecutive relationships. No dot means neither applies.

How to Play Kropki Sudoku

Standard Sudoku rules apply.
White dot: the two adjacent digits differ by exactly 1 (consecutive).
Black dot: one digit is exactly double the other.
No dot: the digits are NEITHER consecutive NOR in a 1:2 ratio.
Between 1 and 2, a black dot is shown (since both rules apply, black takes priority).

💡 Pro Tip

The 'no dot' constraint is just as powerful as having a dot — it eliminates many possibilities.

What does the absence of a dot mean?

It means the two adjacent cells are NEITHER consecutive NOR in a 1:2 ratio. This negative constraint eliminates many candidate pairs.

Why is the dot between 1 and 2 always black?

Both rules apply — they're consecutive AND in a 1:2 ratio. By convention, black (ratio) takes priority over white (consecutive).