Logic Masters Deutschland e.V.

---- RULES ----

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

Shading: Shade some cells in the grid such that in each row, column, and 3x3 box exactly 2 cells are shaded. Shaded cells cannot touch each other, not even diagonally.

Summing Loop: Draw a 1-cell-wide loop (orthogonally connected cells) through the unshaded cells, such that each 3x3 box is visited at least once. The loop cannot touch itself orthogonally but may touch diagonally. The loop acts as a region sum line. Numbers on a region sum line have the same sum in each 3x3 box the line passes through. If a line passes through a 3x3 box multiple times, each individual segment sums separately.

Outside clues: The clues given outside of the grid fulfill the following 3 roles:

• they indicate how many unshaded cells are in between the two shaded cells of that respective column or row.
• they give the total number of loop cells in that respective column or row.
• they act as Skyscraper clues. Numbers in the grid represent the heights of skyscrapers, and clues on the outside of the grid indicate the number of skyscrapers visible in that row or column, looking in that direction. Larger skyscrapers obscure smaller skyscrapers from vision.

Killer cages: Digits in a dotted cage sum to the small number given in the top left corner of the cage.

Kropki dots: Cells connected by a white dot contain consecutive digits.

---- LINKS ----

Solve this puzzle in the CtC app

Solve this puzzle on f-puzzles.com

---

This is the second sudoku in 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
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

---