Crossroads
(Published on 3. April 2023, 13:12 by Knickolas)
This puzzle is a standard chaos construction with a new twist:
Add 9 "crossroad" cells into the grid that allow regions to pass over each other! This adds for some really neat logic that I hope you all enjoy :)
Rules:
- Chaos Construction: Divide the grid into TEN regions, each consisting of nine orthogonally-connected cells. Each row, column and region must contain the digits 1 to 9 once each.
- Crossroads: Additionally, place 9 crossroad cells in the grid so that there is one in each row and column. Each crossroad cell is shared by two regions that intersect each other perpendicularly. Any region that enters a crossroad cell must exit the cell from the opposite side, unless the opposite side borders the edge of the sudoku grid in which case that region doesn’t leave the cell.
- Arrows: Crossroad cells cannot be on a cell with an arrow. A cell with an arrow indicates the number of cells seen in the indicated direction (including itself). Region borders obstruct vision.
To clarify, crossroad cells do not have region borders around them (except on the edge of the grid)
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Here is an example grid to showcase how the rules interact. The gray cells are crossroad cells.
You can play this puzzle online using:
Good luck!! Feel free to leave a hidden comment if you get stuck and need a hint. I'll respond as fast as I can :)
Solution code: Column 2 and Row 7. (18 digits)
Comments
on 31. October 2023, 06:49 by marcmees
incredible puzzle. thanks.
on 13. August 2023, 06:56 by Knickolas
Updated Ctc Rules
on 31. July 2023, 03:49 by wand
very fun! quite tricky at the beginning trying to get my head around the crossroads cells, but once things click there are some neat deductions around the geometry, even into the irregular portion
the CTC app rules are missing some very helpful clarifications about crossroad cells - namely whether arrow cells can be crossroad cells and that they have no region borders
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@Wand Thank you! I'm happy to see people still coming back to this puzzle as it's one I'm very proud of :)
on 7. April 2023, 21:15 by peacherwu2
This is the best original rules and puzzle I've tried for a very long time! Very beautiful idea!
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@peacherwu2 Thanks a lot! I'm glad you enjoyed it :)
on 3. April 2023, 17:26 by KNT
Lovely idea, and really really fun construction! Though I agree with the comments (both visible and hidden) that the irregular at the end is more challenging than the region building portion, which caught me a bit off guard.
on 3. April 2023, 16:52 by Niverio
Very cool idea! Loved the region building part. The irregular was very tricky though, even though one realizes some intricacies about the ruleset. One more given wouldn't hurt :P
Overall, lovely puzzle, thanks a lot for setting!
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@ Niverio I'm glad you liked it! I wanted the solver to still have to think more about crossroad logic during the irregular sudoku part which is why it probably comes off as a bit hard. The feedback is still greatly appreciated though! :)
