Sweeping Seas (Nurikabe)
(Published on 30. September 2025, 16:19 by gdc)
This puzzle was inspired by High Ground from Agent. According to the testers (thanks everyone!), difficulty should be around 2-3 stars. If you are new to nurikabe, see the example below. Hope you enjoy!
Even Island Nurikabe: All odd digits (13579) must be orthogonally connected with each other. Each 2x2 group of cells must contain at least one even digit (2468).
Odd Sweeper Circles: A digit in a circle is odd and counts the number of odd digits in the (up to 9) surrounding cells, including itself.
Island Size Squares: A digit in a square is even and counts the number of cells in its island. The cells island is the orthogonally connected group of even cells including it.
Example
All odd digits form a single orthogonally connected area. No 2x2 area is entirely odd, but 2x2 areas that are entirely even are allowed. There are 5 "even islands" with sizes 6,2,2,2,4. Not all islands contain a clue and unclued islands might have an odd size. The circles act as "minesweeper" clues for odd digits.
Solution code: The bottom row (row 9) left to right (9 digits)
Comments
on 4. October 2025, 19:40 by Franjo
I love Nurikabe-Sudoku-combinations. So this one was a must for me. Thank you very much for creating and sharing this wonderful puzzle.
on 3. October 2025, 21:55 by Exigus
Great puzzle. I was stuck for quite a bit before realizing I had misinterpreted the rules and forgot to look at the example. After that it was a super smooth solve. Thanks!
on 2. October 2025, 04:38 by gdc
Thanks davidemsa!
Unfortunately, its not possible to just invert the parity and connect up all the evens into a single area. Otherwise I agree it would have been better to have the evens be water since the colors align better.
on 1. October 2025, 20:00 by davidemsa
I can't believe you made me colour odd digits in blue (there's no way I'll have orange water).
Good puzzle, the different aspects interact nicely with each other.
Edit: Since you replied, let me clarify that first sentence is just a joke.
on 1. October 2025, 08:40 by Demparo
Such a fun puzzle!
on 1. October 2025, 03:14 by ViKingPrime
Fantastic. A beautiful blend of logic, all rules sort of passing the baton back and forth.
on 1. October 2025, 01:46 by dzamie
That one island threw me for a loop, being much more used to "one island, one clue" nurikabe puzzles.
Fun, though!
on 30. September 2025, 22:01 by halftime
What a lovely solve! I enjoyed figuring out how the different constraints interact with each other. Thank you for sharing!
on 30. September 2025, 20:39 by sujoyku
What a beautiful puzzle! Thank you, gdc!
on 30. September 2025, 18:33 by Calvinball
If you are new to Nurikabe or if you've been doing Nurikabe for years this is a must solve. Smooth, elegant, approachable, lovely. A true SEAL.
on 30. September 2025, 16:24 by Agent
Very nice and smooth!
