159-Squared
- Killer cages
The brief
- Normal Sudoku rules apply.
- Box 1-5-9: Each digit in box 1 indexes the 1 in that digit’s box in its corresponding box position. The same rule applies to box 5 digits indexing 5 in that digit’s box and corresponding position, and box 9 digits indexing 9 in that digit’s box and corresponding position (i.e if R3C1=6 then R6C7=1, if R4C6=7 then R7C3=5, & if R8C8=3 then R2C8=9).
- Digits in a cage do not repeat and sum to the clue in the top left.