Internal X-Sums (Chaos construction)
(Published on 14. April 2025, 12:00 by Oripy)
I love solving chaos construction puzzles and always wanted to set one myself. I then tried these rules on a 4x4, then on a 5x5 and liked the idea so here is a (hopefully interesting) 9x9.
Rules:- 9x9 Chaos Construction rules apply: Divide the grid into nine non-overlapping regions each consisting of nine orthogonally connected cells. Place the digits one to nine once in each row, column, and region.
- Digits in cells with arrows indicate the sum of the first N digits, where N is the digit in the closest cell to the clue in the direction of the arrow.
- Those N cells are all in the same region, beginning and ending with a region border (i.e. the cell with the arrow and the cell after the Nth cell are in a different region than the N cells).
- If an arrow is external to the grid, the cell with an arrow can contain any number including multi-digit numbers.
- Consecutive pairs: Digits separated by a white dot are consecutive.
Example:
The puzzle:
The puzzle can be solved on SudokuPad
Solution code: Digits of line 4 with a dash "-" for each border crossed (solution code for the example would be 243-5-1).
Comments
on 20. May 2025, 15:32 by Malrog
I plugged away at this over a long period of time, but it is a testament to the puzzle that I never felt stuck or wanted to give up. Fantastic fun solving this one. Thank you!
on 13. May 2025, 10:33 by Snookerfan
Beautiful puzzle with some nice aha moments! Thank you
on 21. April 2025, 16:03 by Agent
Smooth solve and great region building!
on 18. April 2025, 21:40 by askaksaksask
Excellent. I love this rule set, and there is surprisingly a bulk of the puzzle left after the X-sums clues are all handled, which I really liked as a misdirect. Some great CC and region building in store for those who tackle this one... fairly accessible too. Highly recommend. Thank you for this!
on 16. April 2025, 16:28 by cam
Really brilliant puzzle! This is one of the best chaos constructions I've solved in a while. Thanks :)
on 16. April 2025, 01:32 by madhupt
This was real fun and very very smooth! Brilliant setting that led to really cool deductions and some really odd shapes. Thanks for sharing this.
on 15. April 2025, 19:49 by mnhuik
tough and good
on 15. April 2025, 11:39 by MagnusJosefsson
Fun and smooth!
on 15. April 2025, 05:05 by tallcat
Challenging but fun! Definitely threw me for a loop a couple of times :)
on 14. April 2025, 22:39 by Elliott810
Brilliant puzzle! Thank you:)
on 14. April 2025, 21:51 by Steven R
Fun puzzle, thanks for setting :)
on 14. April 2025, 17:37 by rameshsrivats
Tough but terrific.
