Eendracht (159^2)
(Published on 13. September 2026, 01:47 by Nell Gwyn)
- Sudoku: Place the digits 1 to 9 once each in every row, column and box.
- Double 159: Digits in the first, fifth and ninth columns give the position of the 1, the 5 and the 9 (respectively) in their respective rows (for instance, if r4c1 is a 7, then r4c7 is a 1). Similarly, the digits in rows 1, 5 and 9 index those same respective digits in their columns (e.g. if r9c3 is a 6 then r6c3 is a 9).
- Sandwich: Clues outside the grid give the sum of the digits sandwiched between the 1 and the 9 in the indicated row or column (">" and "<" mean "greater than" and "less than" respectively).
- Yes, really.
Solution code: Row 2 followed by row 8 (left to right).
Last changed on on 20. September 2026, 05:16
Solved by SudokuHero, ggwp, SincereEngineer, jalebc, voldemortensen, sandmoppe, Fisherman, bansalsaab, Snookerfan, arctan, PippoForte, SKORP17, mathpesto, Ipit, kangaroo, 72kchunshuai, pdabraham
Comments
on 20. September 2026, 05:16 by Nell Gwyn
Fixed some HTML issues in the rules. The puzzle itself is unchanged.
on 13. September 2026, 15:52 by Snookerfan
Very nice! As someone who is not familiar with double indexing, this was a joy to discover and explore some of the secrets. Thank you
on 13. September 2026, 02:35 by SudokuHero
Good puzzle, I'd say closer to 3* though. Maybe 4* for people unfamiliar with index cells
