Schwarzschild
(Published on 20. July 2026, 20:30 by Jay Dyer)
I've been wanting to post some new puzzles for a while, but other things continue to keep me busy. I set and tested this puzzle a few months back, then it got buried in my to-do list, and I figure it's about time I post it here.
Rules
- Each row, column, and 3x3 region contains the digits 1-8 once each, as well as one empty 'black hole' cell.
- For the purpose of cage sums, a black hole cell has a value equal to the sum of digits in all (orthogonally) adjacent cells, leaving the adjacent cells with a value of zero. A cell may not be adjacent to more than one black hole cell.
- The values of cells in a cage sum to the clue in the cage's corner. Digits may not repeat in a cage, though values may repeat.
Example:
Play online in Sudokupad.
Solution code: Column 7 (with an X marking the black hole cell)
Comments
on 19. September 2026, 11:57 by QuiltyAsCharged
Fantastic puzzle, lovely logic!
Black hole cell
what's your sum
you modify the caaaaaage
Black hole cell
what's your sum, what's your sum, what's your sum
on 1. August 2026, 02:54 by Macarena
Very interesting idea. It was 5* to me. There wasn't a moment of just filling numbers, all the time I had to prove myself to solve. Until the last digits. Very challenging but much rewarding.
on 25. July 2026, 05:24 by Crusader175
Very cool idea!
on 23. July 2026, 20:15 by polcat
Very nice! I found this a borderline 5* puzzle... took me 156 minutes.
on 23. July 2026, 16:26 by Franjo
Thank you very much for creating and sharing this amazing puzzle. Not easy to find the break-in (well, for me at least), but extremely satisfying to get it done.
on 22. July 2026, 14:13 by PierreTombal
I wasn't sure whether the no repeat rule applies to black holes too. At one point I was ready to just gamble it, but I'm glad I didn't.
on 22. July 2026, 06:26 by alexsmart
Amazing puzzle. Especially enjoyed the logic in the bottom three rows.
on 21. July 2026, 18:30 by Fool on Hill
Cool puzzle. Not so hard in the end, but involves a range of varied deductions flowing from the existence of "black hole" cells - quite easy to miss an implication on a first encounter ...
on 21. July 2026, 15:51 by Miatc
Had to start over once, but second attempt was very smooth. Very clever ruleset
on 21. July 2026, 15:49 by Snookerfan
Very nice! Extremely weird ruleset, very rewarding solve, albeit with many mistakes and a lot of backtracking. Thanks
on 21. July 2026, 15:23 by Chelo
It was a bit hard to enter the rules but once in it was a hammer. Thanks a lot Jay for setting and sharing it!..
