Colossal Slitherlink Sudoku
(Published on 5. September 2023, 09:00 by Agent)
I've been wanting to set a colossal puzzle for quite some time, and I really enjoyed the Slitherlink hybrids from pokerke and others on the portal. As per usual in colossal grids, I don't think any particular step is terribly hard, but the puzzle may consume a lot of time. I hope this can inspire some more colossal and/or Slitherlink puzzles in the future! As for me, this is neither the last Slitherlink nor the last colossal puzzle I intend to create.
Rules
- Slitherlink: Connect some pairs of orthogonally adjacent dots to form a single non-intersecting loop. Clues represent the number of edges drawn surrounding the clue (up to four).
- Numbered Rooms Sudoku: Place the digits 1 to 9 once each in each row, each column, and each box. Clues outside the grid indicate the digit placed in the Nth cell from that direction, where N is the digit in the first cell from that direction.
- Each cell of the Sudoku occupies a 3x3 area (thin borders) of the Slitherlink. The digit placed in that cell indicates the number of cells inside the loop (from 1 to 9) in the respective 3x3 area of the Slitherlink. If a digit is indexed by a Numbered Rooms clue, that digit indicates the number of cells outside the loop instead.
For the answer check, you'll need to shade cells outside the loop, or use green edges.
Solution code: Give the length of the longest contiguous sequence of cells outside the loop in each of the last 9 rows of the Slitherlink, from top to bottom. Then in each of the last 9 columns, from left to right.
Comments
on 30. July 2025, 09:49 by ffricke
Sehr schönes Rätsel, das einige Ausdauer verlangt. Ich war schon auf dem richtigen Weg, habe aber eine mögliche Wegführung übersehen und dann viel Zeit darauf verwendet, alle anderen Möglichkeiten zum Widerspruch zu führen. Also wieder zurück zum Anfang und siehe da, es ging ja doch noch irgendwie weiter.
on 19. June 2025, 09:41 by sfushidahardy
Lovely puzzle! Nothing hard, even for an absolute slitherlink novice. (Took me 2.5hrs)
on 30. April 2025, 19:04 by dumediat
Surprisingly approachable, and loads of really fun interactions. Each deduction leads to the next beautifully. Thank you so much for this! :D
on 7. November 2024, 20:51 by LeiZ123321
worth all the time it took to solve, very nice!
on 6. April 2024, 17:38 by Piatato
Great fun, although the smoothness overwhelmed me to such a degree that I got careless and did a silly mistake. Awesome construction!
on 25. February 2024, 23:05 by clover
wow
on 2. October 2023, 09:16 by tesseralis
Yay! Finally had time to tackle this. Such a fun journey from start to finish. I really liked how marking the numbered rooms clues added a little twist to the slitherlink grid!
on 6. September 2023, 23:14 by Jesper
Lots of fun, the smoothest solve I've had of a colossal puzzle
on 6. September 2023, 09:38 by MagnusJosefsson
Amazing puzzle! So very smooth with little risk of making mistakes or getting stuck. Very fun and rewarding to see everything gradually resolve!
on 6. September 2023, 02:33 by MicroStudy
a truly epic adventure
on 6. September 2023, 00:58 by Christounet
Brilliant stuff ! I’m glad you did set a colossal hybrid as I hoped after you solved mine :)
An amazing journey and a very interesting new layer in the indexing with the numbered room. Thans !
on 5. September 2023, 21:27 by samuel1997
What an extraordinary puzzle! This is my first time to finish this kind of puzzle, and it took me 6 hours! I am definitely not regreting it though, it brings me lots of joy!
on 5. September 2023, 17:21 by KNT
The one thing this puzzle succeeds at above all else (in my opinion) is just being really fun. Thanks for this! really cool and I think noticeably easier than other colossal puzzles I have solved.
on 5. September 2023, 15:19 by wooferzfg
Awesome puzzle, thanks! So much cool connectivity logic.
