Negative Constraints Rule!
(Published on 19. September 2025, 08:27 by Md88keys)
by Md88keys
Play in Sudokupad
Normal sudoku rules apply.
Dominos are orthogonally connected pairs of cells.
1. In the entire grid, every domino that sums to 10 is marked with an X, and every domino that sums to 5 is marked with a V.
2. In each 3x3 box, all dominoes that sum to 9 are indicated by cages.
3. In each 3x3 box, any remaining uncaged cells which are dominoes that sum to 11 are also caged.
All rules result in negative constraints. All XV pairs are given. All 9 cages within a box are given. All remaining 11 cages are given.
Note: It is possible that a cell forms a domino that sums to 11 with a 9-caged partner cell. That is not given because the 9-cage is marked first.
Solution code: Row 1
Comments
on 5. October 2025, 18:35 by snuuba
Really cool puzzle.
I tried it few days ago and got nowhere, but today it clicked and felt like 2 stars, weird experience.
Many thanks
on 22. September 2025, 23:24 by dzamie
Had to come back to this one after a new day to see what I'd missed. What a cool way to do negative constraints, particularly with the order of operations on the 9-cages vs 11-cages.
on 20. September 2025, 15:38 by SquareCat
Love a negative constraint puzzle! Makes you think backwards in a way. Very fun, thank you!
on 19. September 2025, 19:31 by Ragna
Fun puzzle! A bit confusing. Thank you for sharing. :-)
on 19. September 2025, 15:37 by blackjackfitz
I really, really liked this puzzle. Thank you!
on 19. September 2025, 14:49 by wuc
To me rather 3*. Takes some time to consider all rules. Very refreshing fun puzzle thx.
