Box Brain Sudoku
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Easy · technique 6 of 18
Kropki Dots
Dots fix how neighbouring digits relate.
A Kropki sudoku technique.
How it works
Keep only digits with a partner next door: one apart for a white dot, double or half for a black dot, neither when there is no dot.
A worked example
White dot: the cells in row 1, column 3 and row 1, column 4 hold consecutive digits, so the cell in row 1, column 4 cannot be 7 or 9.
- The cells that make the pattern
- Candidates it rules out
A real position from a puzzle in the app. Small digits are the candidates the step looks at; coloured digits are already solved.
Practise it in Box Brain Sudoku
The app teaches Kropki Dots on this same board, then hands you puzzles that need it. When you are stuck mid-game, a hint first points you to the right area, then names the technique and shows the move.