Out of Touch
(Published on 22. August 2026, 17:33 by varepsilon)
Normal Sudoku rules apply: Place the digits 1–9 exactly once in every row, column, and 3×3 box.
Draw a single closed loop that moves orthogonally through cell centers. It must leave exactly nine cells unvisited and visit every other cell exactly once.
The nine unvisited cells contain 1–9 once each, with no two in the same row, column, or box. A cell is unvisited if and only if its digit equals its position within its box.
The loop can be divided into nine consecutive 8-cell sections, each containing eight different digits. For each section, the unvisited cell containing its missing digit may not share an edge with any cell in that section.
Solution code: Digits in row 2 cells where the loop turns, read from left to right.
Comments
on 10. September 2026, 20:30 by jaredbitz
Really nice, and great fun to solve.
on 7. September 2026, 13:44 by JoeyJoeJoe
01:47:32 for me - thank you for setting!
on 6. September 2026, 12:13 by xsansara
Really great logic, once you understand it. Please make more of these!
on 6. September 2026, 00:54 by booteskey
Very cool, would love to play more like this.
on 6. September 2026, 00:01 by GG_70
I found the wording of the last rule a little confusing but smooth logic after that
The missing digit of a section may not be that of any unvisited cells with which they share an edge.
on 2. September 2026, 05:59 by Agent
Cool puzzle! It became a lot smoother once I noticed the "if and only if".
on 27. August 2026, 19:32 by Fool on Hill
Excellent puzzle - a joy to solve. Never brutal but always a challenge.
on 27. August 2026, 13:33 by The Book Wyrm
Really cool puzzle!
Interesting ruleset and very well executed.
on 25. August 2026, 21:49 by Myxo
Brilliant!
on 25. August 2026, 05:08 by Gnosis66
This was a very clever & challenging puzzle. It was also distinctive. I’ve never seen anything like these constraints before.
on 23. August 2026, 13:22 by lmdemasi
This was a really enjoyable puzzle. The initial portion was really interesting, and the scanning in the second half was quite challenging but always fair.
on 23. August 2026, 04:27 by varepsilon
Updated the solution code to reflect which cells are on the loop.
