Nurikabe Sweeper
(Published on 23. May 2022, 01:37 by KNT)
While the rules might take a moment to wrap your head around, just read them carefully and it will make sense- they are simpler than they might seem at first glance. I hope this puzzle is more on the approachable side.
Rules:
1) Normal Sudoku rules apply.
2) Shade some of the squares blue (ocean), and the others green (island). The ocean must all be orthogonally connected, and not have any 2x2 blocks.
3) Digits on an island may not repeat, and must include the digit that is the total number of cells of that island (i.e., a 2 cell island must contain the digit 2). Islands may not touch orthogonally, but they may touch diagonally.
4) Numbers outside the grid give the sum of island cells in that row or column.
5) Lastly, a digit in a circle indicates how many of the 8 surrounding edges and corners to that cell are part of the boundary of an island.
Here is a 6x6 example puzzle to help illustrate the rules:
Note how the edge of the grid is used in the sweeper counts in the ruleset. As you can see in the example, the 3 circle in R1C1 does not count the edge of the grid, while the 6 in R1C3 does. This is because in R1C3, the border of the island consists of the edge of the grid.
The full puzzle is shown below.
Solution code: Column 8
Comments
on 20. April 2024, 17:09 by The Book Wyrm
Nice puzzle!
Good flow, and lots of interesting deductions. Never too difficult, but never easy either.
on 5. August 2023, 19:25 by StephenR
KNT's puzzles often seem to do my head in, and often I break them or think I have broken them when I haven't. It must say something about their quality that I continue to come back to them. This was another excellent one which flowed at times and had my head-scratching muscles fully exercised at other times.
on 10. June 2023, 21:10 by ibag
Wonderful!
on 12. September 2022, 16:48 by Agent
Very enjoyable puzzle! The edge sweeper ruleset works very nicely with nurikabe.
on 23. August 2022, 01:20 by Piatato
Great puzzle! I had some big struggles spotting some very basic nurikabe logic some times. Maybe one beautiful day some time in the future, pencil puzzles will feel less frightening to me than they do now, haha!
on 22. June 2022, 20:18 by PixelPlucker
Wonderful puzzle, thanks! Great variety of logic, and the solve path felt intentionally designed throughout
on 5. June 2022, 11:04 by Christounet
Very nice trip around these islands ! And quite approchable compared to what we're used to with your puzzles ! Thanks.
on 24. May 2022, 23:29 by kolot
Very enjoyable puzzle! Not too difficult and fun to solve. Well done!
on 23. May 2022, 22:40 by Mr.Menace
Very nice puzzle! The ending was great indeed, made me laugh!
on 23. May 2022, 20:15 by Niverio
Very nice hybrid! Cool ending too.
on 23. May 2022, 19:39 by twobear
Great puzzle with very smooth solve. Thank you!
on 23. May 2022, 15:37 by Playmaker6174
Probably I didn't solve that many Nurikabe puzzles but that was so tricky for me, there're lots of potential traps throughout the solve but everything worked really well together and there're lots of brilliant deductions too. Thank you for this great journey x)
on 23. May 2022, 15:19 by Vebby
Very enjoyable! Loved how all the rules came into play in order to make progress. Thanks KNT :)
on 23. May 2022, 12:11 by Jesper
A beautiful puzzle, thanks!
on 23. May 2022, 11:46 by LittleBallOfPurr
Gorgeous puzzle, love the water theme. Challenging, yet approachable with baby steps. Hope to see more of this style/theme, many thanks!
on 23. May 2022, 10:07 by RJBlarmo
Really cool puzzle! Few times I thought I broke it but everything worked out. Fun disambiguating logic at the end.
