Six Loop
(Published on 25. August 2025, 06:06 by oskode)
I got the idea for this puzzle about 6 months ago. The resulting logic from this constraint gives off a very "classic sudoku" vibe, with a lot of focus on scanning. If that's not your cup of tea, then maybe sit this one out.
This is the first one of three Six-Loop puzzles I will be publishing this week, the next one ramping up the difficulty and the last one adding FOW. Enjoy!
Rules:
- Sudoku: Fill all rows, columns and marked 3x3 regions with the digits 1-9 without any repeats.
- Six Loop: Draw a cell-wide loop in the grid, passing through the centers of orthogonally adjacent cells. The loop does not touch itself, not even diagonally. Any group of six adjacent cells along the loop must contain different digits.
- Circles: A cell containing a circle is part of the loop and indicate how many loop cells it sees vertically and horizontally (including itself). Non-loop cells blocks vision.
- Squares: A cell containing a square is not part of the loop and indicate how many non-loop cells it sees vertically and horizontally (including itself). Loop cells blocks vision.
Click here to play online!
Ratings and comments are very much appreciated. Thank you for playing!
Solution code: Digits on the loop in column 3 (top to bottom) and column 4 (top to bottom)
Comments
on 22. October 2025, 22:45 by Bankey
Lovely puzzle. Very creative ruleset, well-executed. Thanks, @ oskode, for setting and sharing :).
on 22. October 2025, 13:06 by oskode
Specified loop width
on 22. October 2025, 11:06 by Bankey
@ oskode, one clarification pl : is it a one-cell wide loop, or a line loop? The two kinds would be differently impacted by the not-touching-itself condition. The doubt arises due to the rule wording "... passing through the centers of... ". (Or, is it a part of the puzzle to figure this out?). Thanks.
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It’s a one-cell wide loop, thanks for pointing that out! I’ll change the wording of the rules
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Thanks for your response :).
on 29. August 2025, 21:18 by QuiltyAsCharged
Excellent puzzle! I enjoy loop building and I was in the mood for a challenge, so I gave it a try although scanning and classic sudoku is not my strong suit.
It was a hearty challenge, as advertised. It requires a patient attention to detail, but it's very rewarding to make progress step by step.
There is a moment that's just sublime where the final piece of the path and the final circles/squares get resolved together. Bravo!
on 26. August 2025, 16:42 by Snookerfan
Lovely puzzle! I found the scanning with the six loop rule very hard, therefore my rating of 5 stars. I am glad to make it through the puzzle in the end. Thank you!
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Glad to hear you liked it! I actually forgot to change the difficulty to 4*, my bad!
on 25. August 2025, 10:29 by Philologos
Amazing puzzle! I really enjoyed the “classical sudoku” vibe towards the end.
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Thank you very much, glad you enjoyed the vibes!
