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.
Special Thanks
The original inspiration for this puzzle was Borderland (3/5) by Richard.
Following chats with gdc and palpot about how best to present this puzzle, I finally settled on this title, version and rules; which is closer to the following puzzles:
- The Big Beach Parity (1/5) by gdc, and,
- Parity Islands (3/5) by yttrio
To play the puzzle, please click the image:
Initial Setter Difficulty: 2.5-3 / 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.
Parity Islands
Orthogonally connected groups of cells with the same odd/even parity are called 'islands'. A digit in a circle counts the number of cells in its island. Islands may have multiple circles. Not all possible circles are necessarily given.
Hint to start
I would recommend colouring parity. Keeping circles apart that are in the same row, column or box is important, otherwise they would need to be the same value/digit. 1 (odd) in Row 8 is the only Flat Mate for 5 (odd) in Row 9 - this impacts circle options in Row 8.
Visual Rules Example:
Solution code: Row 1 Digits
on 10. June 2026, 19:49 by da-hans
Very nice puzzle
on 10. June 2026, 19:35 by Qodec
Puzzle of the year (so far) for me. I wish I could set something like this. What a gem!
(Edit: high5 @galium_odoratum)
on 10. June 2026, 17:50 by pmays123
Beautiful puzzle. Very fun to solve. Thanks!
on 10. June 2026, 16:15 by Snookerfan
Great puzzle with some brilliant steps. Those steps were 3-4 stars, my solve time overall was 2, so 2.5 to 3 stars for difficulty, 5 for beauty. Thanks
on 10. June 2026, 12:44 by Franjo
Thank you very much for creating and sharing another beautiful DFM-puzzle. Wish there were more Parity Islands puzzles!
on 10. June 2026, 11:49 by galium_odoratum
Step 1: Reading the DFM-rule.
Step 2: Reminding myself to not forget the DFM-rule.
Step 3: Forget about the DFM-rule anyway and getting stuck.
Step 4: Reading the rules again to remember the DFM.
Step 5: Solving a very smooth and beautiful puzzle, thank your for setting this gem.
Step 6: Add it to my favourites.
on 10. June 2026, 11:30 by Crusader175
Fun puzzle!
on 10. June 2026, 09:21 by Piatato
Smooth!
on 10. June 2026, 09:08 by Elliott810
Brilliant puzzle! Thank you:)