Big Zipper Islands (Nurikabe)
(Published on 5. February 2026, 16:43 by gdc)
The 9x9 version of my previous 6x6 puzzle Zipper Islands. According to testers (thanks everyone!), the difficulty should be right between 2 and 3 stars.
Modified Nurikabe: Draw 8 lines of length 2 or more such that each circle is the center of one of these lines. The lines only move orthogonally and may not touch themselves or each other orthogonally. Each 2x2 must contain at least one cell on a line. Non-line cells form a single orthogonally connected area.
Zipper Islands: Digits an equal distance to the (circled) center of a line sum to its central digit.
Partial Suguru: Digits never repeat on lines. Circles marked with "S" also count the number of cells on their line.
Ambiguous Cave: A digit in a diamond is of either "type" (line or non-line) and counts how many cells of its own type it sees in the row and column combined, including itself. The other type blocks vision.
Example
In this example, line-cells (zipper islands) are colored green and non-line cells are colored blue. The diamond in the middle sees 1 cell to the left, 2 cells on top and itself (1+2+1=4).
Solution code: Cells on lines (zipper islands) in row 7, left to right.
Comments
on 3. April 2026, 10:15 by Scorps
Lovely logic, 35 minutes for me, thanks for sharing!
on 21. February 2026, 21:18 by silent_rob
Thanks for the excellent puzzle! Lovely combination of nurikabe and zipper logic that led to interesting and enjoyable deductions.
on 21. February 2026, 13:48 by wuc
You made me a big nurikabe fan with your puzzles. Great setting thx.
on 8. February 2026, 19:17 by damo_89
Gorgeous, super smooth, 2 stars for me. Great introduction to nurikabe hybrids.
on 5. February 2026, 19:40 by Wuschel
Very nice and approachable, thank you!
on 5. February 2026, 18:56 by Rockon101000
Loving the nurikabe puzzles recently, and this was a great twist! Took me 40 minutes, I agree with the 2.5 star rating.
on 5. February 2026, 16:53 by Oddlyeven
Very fun and enjoyable puzzle! Thanks!
