Logic Masters Deutschland e.V.

Chaos Construction: X-Sums / Sandwich

(Published on 13. April 2022, 17:12 by KNT)

Place the numbers from 1 to 9 exactly once in every row, column, and region. Some numbers are already given. Each region is orthogonally connected and must be located by the solver.

A clue outside the grid can mean one of two things, as written below. A question mark indicates a nonzero, positive valued number.

1. A number outside the grid indicates the sum of the first N numbers from the direction of the clue, where N is the number closest to the clue. The first N numbers are also all in the same region, and the N+1th number is in a different region.

2. A number outside the grid indicates the sum of the numbers between the 1 and 9 in that row or column. The numbers between the 1 and the 9 are all in the same region, and that region does not include the surrounding 1 and 9. If two clues share the same row or column, they cannot both be this type.

SudokuPad

penpa+

Solution code: Type the digits (no spaces) of the region containing R5C5 as follows: Row 1's digit in the region (left to right), Row 2's digits in the region (left to right), etc. 9 digits total.

Last changed on on 11. June 2024, 22:20

Solved by Dandelo, kolot, ___, marcmees, TotallyNormalCat, lerroyy, Elliptical, Christounet, MagnusJosefsson, jkuo7, Jesper, Lizzy01, rmn, wenchang, tinounou, hepcecob, Statistica, fjam, pianobarry87, ns08, ... harrison, AnnaTh, Mody, Myxo, StephenR, OGRussHood, SKORP17, dogfarts, misko, flyjim, Euclid, ibag, Tom-dz, Feadoor, h5663454, laky, Saskia, Uhu, Nick Smirnov, The Book Wyrm, Las4one, steeto
Full list

Comments

on 29. January 2024, 23:10 by The Book Wyrm
Very good puzzle!
Interesting ruleset, and the ambiguity makes things quite hard at times. Definitely requires a lot of thinking about the implications of the rules to get started, but flows very smoothly after that, with lots of nice deductions.
Also like how the ? clues, while initial useless, end up having forcing some nice logic.

on 6. May 2023, 17:34 by ibag
Wow, another peace of art!

on 4. December 2022, 16:02 by StephenR
Loved this, thanks. But I did get horribly snagged up at a particular point. Once I'd spotted the logic, which wasn't actually that difficult, the remainder of the path was very smooth.

on 16. August 2022, 23:03 by Piatato
Delicious!

on 27. July 2022, 19:34 by peacherwu2
What a masterpiece! Enjoyed every minute of it!

on 17. July 2022, 17:07 by Snookerfan
What a great puzzle again! I loved the power of the ? clues. Thank you KNT!

on 10. July 2022, 08:18 by PrimeWeasel
Smooth solve!

on 14. April 2022, 14:45 by Christounet
Very nice combination of X-sums and Sandwiches in a chaos construction ! A great first sequence which felt more like a 5 stars to me. Many thanks to you for setting this !

on 13. April 2022, 22:37 by lerroyy
Very nice puzzle!

on 13. April 2022, 21:36 by TotallyNormalCat
Clean puzzle :)

on 13. April 2022, 21:31 by marcmees
Nice. thanks.

Last changed on 13. April 2022, 19:56

on 13. April 2022, 19:55 by Dandelo
I wasn't terrified, because in the last weeks and months I've seen so many CC monsters ...

As always: It's not easy to understand the consequences of a new rule set. But solving the puzzle itself was quite smooth.

Last changed on 13. April 2022, 19:29

on 13. April 2022, 19:23 by kolot
This puzzle is definitely not a monster. It is hard but involves reasonable logic. It is fun to solve.

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Thank you for the solve, kolot! I too do not think any step in this puzzle is monstrously difficult, but, like many real world monsters, they are more terrifying in appearance than anything else :)

Last changed on 13. April 2022, 19:29

on 13. April 2022, 18:56 by Dandelo
Very nice.

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Thanks, Dandelo!

Difficulty:5
Rating:97 %
Solved:56 times
Observed:7 times
ID:0009N5

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Solution code:

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