Solo
(Published on 23. November 2025, 10:00 by Kaktuslav)
Rules: Normal sudoku rules apply.
Solo cages: The digit in a cage counts how many of the (up to nine) 3×3 squares that include the caged cell contain no other instance of that digit.
E.g., if R2C3 = 4, then among the six 3×3 squares that include this cell, exactly four contain no other 4.
Solution code: Row 5
Comments
on 25. November 2025, 20:33 by Ikke Moon
Great explanation of the rules. Thinking about them for more than 15 minutes and still don't know what you mean (non native speaker, must be my handicap).
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K: Let me try to elaborate — I hope this will be helpful. For each cage (say containing the digit N) in the grid, consider all 3×3 squares of nine cells that contain this cage. There are at most nine such squares, but possibly fewer (e.g., R2C3 is included in only six such squares — those with top-left cells in R1C1, R1C2, R1C3, R2C1, R2C2, and R2C3). Among these 3×3 squares, there are exactly N that contain just one occurrence of the digit N (i.e., this digit does not repeat within this 3×3 square outside the considered cage).
on 24. November 2025, 19:50 by flutchman
Brilliant idea and great execution. Nice puzzle.
on 24. November 2025, 14:24 by Franjo
Interesting and unusual constraint, I needed a second attempt to find my way through - and gave 4*. But I really did enjoy it a lot. Thank you very much for creating and sharing this great puzzle.
on 23. November 2025, 15:15 by Qodec
Refreshing and very interesting!
