Nurikabe Loop by Murat Can Tonta
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Author/Opus: This is the 125th puzzle from our contributing puzzlemaster Murat Can Tonta.
Rules: In this variation of Nurikabe, the no 2×2 ocean rule is removed and instead all ocean cells must belong to a single closed loop.
Specifically: Divide the grid into regions called “islands”, each containing exactly one of the given numbers and with the same area as that number. Islands can only touch diagonally. A single closed loop (without intersection or crossings) must be drawn in all remaining cells.
Answer String: Enter the length in cells of the horizontal loop segments from left to right in the marked rows, starting at the top. If the loop only has vertical segments in the marked row, enter 0. Separate each row’s entry with a comma. This example has the key “12,3”.
Time Standards (highlight to view): Grandmaster = 5:30, Master = 10:15, Expert = 20:30
Solution: PDF; a solution video is also available here.
Note: Follow this link for classic Nurikabe puzzles on this website and this link for other variations on Nurikabe puzzles. If you are new to this puzzle type, here are our easiest Nurikabe puzzles to get started on. More Nurikabe puzzles can be in The Art of Puzzles, in our beginner-friendly book Logic Puzzles 101, and in the e-book Nurikabe by Ashish Kumar.
Excellent puzzle.. superb solve path..
Good solve path, but I spent too much time proving it can’t be solved as a regular Nurikabe. Perhaps one or two tweaks would make it a good alternate regular puzzle, though very hard; e.g., changing 13 to 17 does almost all of it, but is probably incomplete or nonunique. Once I corrected myself I found it was a much better puzzle than I expected.