Logic Masters Deutschland e.V.

While the weather forecast predicts foggy conditions throughout the day, a Dutch hiker on his vacation in the Austrian Alps decides to climb a nearby mountain. Help the hiker navigate through the fog. The hiker starts at his car parked on the marked parking place and must return to his car after the hike. During his journey, the hiker sings Dutch hiking songs. Along the path, signposts help the hiker to stay on track, which must all be visited to not get lost. After passing over the summit, the hiker walks to the nearest station and takes a cable car down to the base of the mountain, before returning to his car.

---- RULES ----

Normal Sudoku rules apply: Fill the grid with digits 1 to 9 appearing once each in every row, column, and 3x3 box.

Fog of War: The grid is partially covered by fog. When a correct digit is placed, the fog will be lifted from the surrounding cells.

Hiking loop: Draw a single 1-cell-wide loop of orthogonally connected cells into the grid that enters no cell more than once. The loop starts at the marked parking spot, passes by all signposts and crosses the mountain top. Until reaching the summit, the loop can never move down, only left, right, or up. On the way down, the loop must run along the cable car line.

Dutch Whispers Line: The loop segment from the bottom cable car station via the parking spot, the signposts and the summit to the upper cable car station must be a valid Dutch Whispers Line. Adjacent digits along the loop must differ by at least 4.

Cable car: Digits along the grey cable car line, connecting the two stations (illustrated as houses), must have alternating polarity, oscillating between low (1234) and high (6789).

Signposts: Cells with a signpost, illustrated by arrows, must be visited by the loop and the arrow points towards the next cell on it.

Kropki dots: Cells connected by a white dot contain consecutive digits. Digits in cells connected by a black dot are in a 1:2 ratio.

X-clues: Cells connected with an X must sum to 10.

---- LINKS ----

Solve this puzzle in the CtC app

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This Sudoku is part of my series of "build-your-own-loop Sudokus". If you liked solving this puzzle or if you prefer other combinations of loop logic and constraints, feel free to give the other sudokus of the series a go too:

	Loop Logic	Loop Constraint	Further Constraints
Entropic-Zipper- Loop	Counting Cells	Entropic Line	Zipper Lines X-clues
Hiking-through- the-Fog Loop	Signposts	Dutch Whisper, Polarity Line	Kropki Dots X-clues
Renbanimo Loop	Pentominos Guiding Cells	Renbanimos	Kropki Dots Odd cells
Deceiving Loop	Wrogn Clues	Wrogn Clues	9 different constraints
Count-the- Whispers Loop	Counting Cells	German Whispers	Kropki Dot
Whisper-me- Sum-thing Loop	Line-sums	German Whispers	Kropki Dots
Road Running Loop	Road Runner	Parity Line	Kropki Dots
Magically Modifying Loop	-	Incrementers, Decrementers, Nullifiers	Magic Squares, Killer cages, Kropki Dots
Skiing Loop	Gates	German Whispers	Kropki Dot, Between Lines
Behaving Loop	3x3 boxes	Polarity Line	Kropki Dots
Magical Loop	Guiding cells	Modular Line	Magic Squares
Foggy Loop	Guiding cells	Parity Line	Fog of War, Killer Cages
10-Suȵ Loop	Moon-or-Sun	10-Line	Killer Cages
Counting Loop	Galaxies	Counting Line	Killer Cages, Kropki Dots, Quadruple Clues
Shining Loop	Moon-or-Sun	Parity Line	Killer Cages
Interfering Loops	Slitherlink + Masyu	Entropic Line + Parity Line	Killer Cages
Slithering Loop	Slitherlink	Entropic Line	Killer Cages, Little Killer
BigBang Loop	Galaxies	Parity Line	Row/Column Indexer, Kropki Dots
Summing Loop	Star Battle	Region Sum Line	Killer Cages, Skyscraper, Kropki Dots
Whispering Loop	Star Battle	German Whispers	Sandwich Sum