Normal sudoku rules apply.
All clues work modulo 9.
White dots:
- Digits separated by a white dot must be consecutive, i.e. one of the digits is congruent to one more than the other digit modulo 9.
- Not all white dots are necessarily given.
- For example, 1 and 9 are consecutive, since 9 + 1 is congruent to 1 modulo 9.
Black dots:
- Digits separated by a black dot must be in a 2:1 ratio, i.e. one of the digits is congruent to twice the other digit modulo 9.
- Not all black dots are necessarily given.
- For example, 5 and 7 are in a 2:1 ratio, since 7 * 2 = 14, which is congruent to 5 modulo 9.
Red dots:
- Digits separated by a red dot must be BOTH consecutive AND in a 2:1 ratio.
- ALL possible red dots are given.
For clarity, two digits separated by a white dot are NOT in a 2:1 ratio and two digits separated by a black dot are NOT consecutive.
Killer cages:
- The sum of the digits in a cage is congruent to the digit in its top-left corner modulo 9.
- Digits may not repeat in a cage.
Leading diagonal:
- The sum of the digits along the leading diagonal (i.e. along the grey line) is congruent to 7 modulo 9.
- Digits may repeat along the leading diagonal if allowed by the other rules.
Play the puzzle here: SudokuPad