Expansion
- Fog of war
- Anti-knight
- Kropki dots
- XV and number dots
- Arrows
The brief
- Normal sudoku rules apply, i.e. each row, column and 3x3 region has to contain the digits from 1 to 9 once each.
- Fog of War: The grid is partially covered with fog. Correctly placed digits will clear the fog around that cell. No guessing is required.
- Anti-Knight: Cells a knight's move (in chess) apart may not contain identical digits.
- XV: Digits joined by a V sum to 5. Digits joined by an X sum to 10. (Not all XV are given.)
- Kropki: Digits joined by white dot are consecutive. Digits joined by a black dot have a 1:2 ratio. (Not all dots are given.)
- Arrows: Digits along an arrow sum to the digit in the circle from which the arrow emerges.