Dutch Flat Mates: Confetti Sums
(Published on 7. January 2026, 07:00 by Flinty)
Previous Dutch Flat Mate Puzzles
This has been a weekly series since '18 Oct 23'. Here is a spreadsheet link for all the previous puzzles in the series, which also has a few teasers for upcoming constraints/guest setters in the series (subject to change).
This alternative link offers a limited LMD search for Dutch Flat Mates.
To play the puzzle, please click the image:
Puzzle Link: Click Here
Initial Setter Difficulty: 2-2.5 / 5
Normal Sudoku rules apply
Place the digits 1-9 so that they do not repeat in any row, column, or 3x3 box.
Dutch Flats
Every 5 in the grid must have a '1' directly above it or a '9' directly below it. It may have both, but it doesn't need both.
Confetti Sums
In ALL cases where the sum of two horizontally or vertically neighbouring digits is A or B; a circle is given. A and B stand for different numbers to be deduced
- White is always A
- Black is always B
- Grey is ambigous, and is either A or B.
Hint to start
A and B are heavily restricted by maths/options in Boxes 2 and 8, with Flat Mates in C5 being the key. The negative constraint is hugely powerful throughout the solve.
Guest Setter
Another series debutant next week, another "A-Tier Setter" series debutant at that! Qodec with Between Lines!
Busy Week For Flat Mates
The wonderful puzzle pack Zodiac x Flat Mates from ViKingPrime had a small issue with Puzzle 6. This has been resolved and I do hope you give it another try!
We also had bonus Flat Mates from aqjhs in the form of a CTC Discord Secret Santa gift for me which is great and well worth checking out: Dutch Flat Mates: Dual Duel. As well as the Scojo Discord Prompt "Wheel" spinning Squisdoku and Flat Mates, so puzzles with those combinations should be making an appearance on LMD.
Solution code: Row 1 Digits
Comments
on 14. January 2026, 21:15 by Gnubeutel
That was pretty tough until i remembered the negative constraint. It was still tough after that, but also before.
on 12. January 2026, 15:58 by Rockon101000
Very nice and challenging puzzle. Took me 80:29 over two days, but the last 20 minutes were so satisfying as I watched the puzzle collapse.
on 11. January 2026, 21:25 by macaco3001
The idea behind this looks lovely, but as a beginner I'm totally lost on how to break in! I can ease past 1 starts and most 2 stars, some 3 stars as well, but I'm perplexed on how to approach this even with the hint, I made barely any progress at all, I do wish there were some easier confetti sums puzzles out there
on 8. January 2026, 13:25 by Flinty
Capitilsed the word "ALL" in the rules to emphasise the negative constraint.
on 8. January 2026, 05:13 by aqjhs
excellent use of the negative constraint
on 8. January 2026, 02:08 by SanFranSam
I did solve it without the hint but I think the negative constraint could have been stated more clearly. Wouldn't have solved it but for damo_89's note.
on 7. January 2026, 16:06 by Franjo
Thank you very much for creating and sharing another lovely DFM-puzzle.
on 7. January 2026, 08:59 by damo_89
Don't forget the negative constraint!
Flinty: Don't be a dozy sausage! x
