What Am I Missing?
(Published on 15. September 2025, 08:00 by Kaktuslav)
Rules: Fill the 8×8 grid with digits 1–9 so that each row and column contains eight different digits, i.e. exactly one digit is missing from every row and every column. Moreover, no two columns are missing the same digit (note there is no similar assumption about rows). On vertical lines, adjacent digits must sum to the digit missing from that column. On horizontal lines, adjacent digits must differ by the digit missing from that row.
Solution code: Negative diagonal (top-left to bottom-right, no spaces)
Comments
on 1. September 2026, 12:58 by simontherry
Much harder than expected, I needed a lot of bifurcation for this one. Must be something I didn't quite get about the puzzle. Went smooth until I got all columns, and then had to try a lot of combinations that turned out to be wrong to eliminate options
on 8. June 2026, 02:20 by kasperd
This puzzle is a lot easier once you read the rules correctly.
For the longest time I thought the difference rule applied in both directions. And I didn't understand how this could be rated any less than five stars for difficulty.
on 16. September 2025, 16:10 by Exigus
Very interesting concept, not too hard with a bit of goodliffing. Thanks!
on 15. September 2025, 12:23 by Kaktuslav
Emphasizing that there is no assumption about rows
