Dutch Earthquake
(Published on 3. January 2025, 13:53 by Gnubeutel)
Rules
Normal Sudoku rules apply. Place the digits 1-9 in every row, column and box exactly once.Skyscrapers: clues outside the grid give the number of skyscrapers visible in the column or row from the direction of the clue. A skyscraper has the height of its cell's value. A skyscraper is only visible if no higher skyscraper blocks the view.
Dutch Flatmates: each 5 needs to have either a 1 directly above or a 9 directly below or both.
Fold-In: The dashed red lines at A and B are folded onto each other so that column 1, 2, 8 and 9 form a secondary grid. In this grid all rules apply, except that regions and rows do not need to have all of the digits (it's a 4x9 grid). Columns 3-7 are ignored for this grid.
E.g. The 4-skyscrapers in row 3 could consist of the values 2, 5, 7, 8 in columns 1, 2, 8 and 9 in the folded grid and of 2, 5, 6, 9 in columns 1, 2, 4, 5 in the regular grid.
Fog: fog covers the board. Some correct digits will remove the fog. (Note: it's dynamic fog to reveal clues or just highlight cells to think about)
Play online with sudokupad.
Note:
The purpose of fog in this puzzle is only to guide the player's focus. The puzzle is playble without the fog, but requires more scanning. Some people don't like being assisted like that. If you want to rawdog the puzzle you can find a fog-free version here. I don't want to hear any complaints that it's no fun having to spot the next bit.
Other Mad Fold-In Puzzles
Solution code: Digits in the fifth column from top to bottom.
Comments
on 28. January 2025, 14:30 by THef of Time
Probably would have been easier on me if I kept those pesky Dutch flatmates in mind. Lovely puzzle
on 18. January 2025, 20:26 by PuzzlePatzer
I wanted to try a Skyscraper Sudoku and stumbled upon this one. I'm glad that I did as it was my first one with fold in. I made a huge mess of it and took me an aeon to finish it but I enjoyed it thoroughly. Thank you for sharing!
on 6. January 2025, 14:49 by ViKingPrime
I'm so pleased to see the Mad-Fold idea take off; it really is a lovely thing when the Sudoku world is gifted a constraint with some longevity.
on 6. January 2025, 00:03 by Gnubeutel
Updated list of other fold-in puzzles to include Origami.
on 5. January 2025, 14:09 by Flinty
Lovely stuff :)
on 4. January 2025, 16:36 by Elytron
Incredibly well thought out puzzle. The skyscrapers combined with Fold-In lines lead to some very interesting logic. I like the fog version of the puzzle, because I was always aware of where to look for the next step. I can highly recommend solving the fog version! :)
