Up to N-urikabe
(Published on 29. October 2025, 21:15 by sujoyku)
Rules:
Sudoku
- Each row, column, and 3x3 region has to contain the digits from 1 to 9 once each.
Nurikabe
- Shade all cells either blue (water) or green (land) such that all water cells are orthogonally connected and form no 2x2 areas. Each area of orthogonally connected green cells is called an island.
Circles
- If a circle cell is water, its digit counts the number of water cells in the (up to) 3x3 area around the clue, including itself.
- If a circle cell is land, its digit counts the number of cells in its island.
Up to N-sums
- A clue outside the Row or Column N indicates the sum of all digits up to the cell that contains the digit N. (The digit N itself is not included in the sum.)
- Moreover, all cells before the digit N have the same shading and the cell containing N has the opposite shading. In other words: The sum entirely consists of water and N is land, or the sum entirely consists of land and N is water.
Here you can solve the puzzle online:
Solution code: Digits in land cells in Column 7 from top to bottom
Comments
on 20. November 2025, 02:47 by daggerMason
Amazing! Three different puzzles in one.
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Thank you, daggerMason! I am glad that you liked it.
Kind regards, sujoyku
on 6. November 2025, 19:25 by chinesemaster
Thank you so much for such a fun puzzle! I love Up-to-N sum so much that I found it to be one of the easiest 4-stars puzzles I've solved! Waiting for a 5-star Up-to-N puzzle to drop!
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Thank you for your comment, chinesemaster! Of course, I am thrilled that you like the Up to N-variant so much and I am glad that you found this to be approachable (for a 4*). Considering a 5* Up to N-puzzle: I rarely ever set 5* puzzles, but let me see what I can do. :)
Kind regards, sujoyku
on 31. October 2025, 23:08 by Christounet
Would gladly solve Up-to-∞ puzzles with this new rule! Thanks :)
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You are much welcome, Christounet, thank you for your fun comment! I am glad that you enjoyed this ruleset.
Kind regards, sujoyku
on 31. October 2025, 09:36 by Bankey
Fun puzzle. Thanks, @ sujoyku :).
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You are much welcome, Bankey, thank you for you comment! I am glad that you had fun solving.
Kind regards, sujoyku
on 31. October 2025, 02:13 by MaizeGator
Nurikabe is obectively an S-tier genre. I've done plenty of them and still found some fresh new ideas in this one. I particularly enjoyed the end and the disambiguation (which I missed for a little while but smacked my head when I saw it)
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Thank you for your comment, MaizeGator! I am glad that you enjoyed the puzzle and found some fresh Nurikabe ideas in this one.
Kind regards, sujoyku
on 31. October 2025, 00:55 by Piatato
Lovely! I predict that you'll have a lot of fun with a wide variety of genres in the not too distant future! :)
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Thank you, Piatato! It is great to hear you enjoyed it. Of course, I have to be stubborn and publically say this is the exception. But why does a little voice inside me say you might be right? :)
Kind regards, sujoyku
on 30. October 2025, 23:49 by StephenR
Delightful puzzle, thanks. Really really smooth. I was quite tired when I started this and wondered if it might be too much, but I couldn't tear myself away. And a nice simple solution code to top it off.
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Thank you for your comment, StephenR! I am glad that you liked the puzzle and had a smooth solve.
Kind regards, sujoyku
on 30. October 2025, 19:39 by tryote
Excellent!!
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Thank you, tryote!
Kind regards, sujoyku
on 30. October 2025, 15:34 by Franjo
Herrliches Inselreich, sehr schöne Konstruktion! Habe allerdings „nur“ 3* vergeben… Heißen Dank für das tolle Puzzle.
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Sehr gern geschehen, Franjo, vielen Dank für deinen Kommentar! Es freut mich, dass es Dir gefallen hat. Was die Schwierigkeit angeht: Ich habe es ursprünglich mit 3* eingestellt. Vielleicht liegt es irgendwo dazwischen.
Herzliche Grüße, sujoyku
on 30. October 2025, 12:49 by marcmees
lots of fun. Thanks
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You are much welcome, marcmees, thank you for your comment! I am glad that you had a fun solve.
Kind regards, sujoyku
on 30. October 2025, 12:04 by Snookerfan
Sublime! A real challenge full of dopamine moments. One of your very best puzzles in my opinion. Thank you!
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Thank you for your kind words, Snookerfan! I am glad that you liked the puzzle and think it is one of my best. That makes me even more proud of it than I have been before. :)
Kind regards, sujoyku
on 29. October 2025, 21:27 by Calvinball
Love a good Nurikabe, and that was a darn good Nurikabe!
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Thank you, Calvinball! It quickly has become a favourite puzzle genre of mine. Great to hear I am in good company. :)
Kind regards, sujoyku
