Since 2021, we have posted some extra difficult Sunday Stumpers, about once a month. These will be quite tough puzzles, but with a logical path to be found (and solution videos to help). This ninth Sunday Stumper of 2022 is a Slitherlink (Switch) puzzle by Matej Uher, author of our new Slitherlink and Variations 2 book. Each clue here has to switch with one of its orthogonal neighbors, so it will be quite a challenge to find the complete loop.

(view directly for a larger image)

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to switch between edgex mode where left click+drag draws lines and right click marks X’s, and a shading and number entry mode to mark/update the switched clues.)

Theme: Knight’s Moves

Author/Opus: This is the 5th puzzle from guest contributor Matej Uher.

Rules: Standard Slitherlink rules. Also, each given clue has to switch its initial position with one of its adjacent neighbors.

Also, see this example:

Difficulty: 5 stars

Time Standards (highlight to view): Grandmaster = 30:00, Master = 45:00, Expert = 1:30:00

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to switch between edgex mode where left click+drag draws lines and right click marks X’s, and a shading and number entry mode to mark/update the liar clues.)

Theme: Bull’s-Eye

Author/Opus: This is the 419th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Variation of Slitherlink rules. Exactly one clue in each row and column is incorrect and must represent another number.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 8:45, Master = 13:30, Expert = 27:00

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: Empty Middle

Author/Opus: This is the 231st puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Standard Slitherlink rules, but any two consecutive line segments cannot have the same length (i.e., on both sides of any turn, the loop must travel different lengths).

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 5:00, Expert = 10:00

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: Snowflake

Author/Opus: This is the 414th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Slitherlink rules (with a hexagonal grid).

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 11:00, Master = 16:00, Expert = 32:00

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between edgex mode where left click+drag draws lines and right click marks X’s and a shading mode to mark inside and outside of loop.)

Theme: Centered Squares

Author/Opus: This is the 4th puzzle from guest contributor Matej Uher.

Rules: Standard Slitherlink rules. Also, an even number of cells in each row and in each column must be inside the loop.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 11:00, Master = 16:00, Expert = 32:00

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: L’s

Author/Opus: This is the 223rd puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Standard Slitherlink rules, but any two consecutive line segments cannot have the same length (i.e., on both sides of any turn, the loop must travel different lengths).

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 5:00, Expert = 10:00

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

(This is a bonus “second” puzzle that is not connected to the usual Monday-Saturday week difficulty.)

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: No Four in a Row

Author/Opus: This is the 2nd puzzle from guest contributor Matej Uher.

Rules: Standard Slitherlink rules. Also, the letters X and O stand for two different digits from 0 – 3.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 2:45, Master = 4:00, Expert = 8:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between edgex mode where left click+drag draws lines and right click marks X’s and a star placement mode)

Author/Opus: This is the 332nd puzzle from our managing editor Serkan Yürekli.

Rules: Standard Slitherlink rules. Also, each row and column must contain exactly two stars (one in the example). Stars cannot touch each other, even diagonally, and all stars must be inside the loop. Stars cannot be placed in the numbered cells.

See also this example:

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 7:00, Master = 14:15, Expert = 28:30

Solution: PDF; a solution video is also available here.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: Inside Job

Author/Opus: This is the 1st puzzle from guest contributor Priyam Bhushan.

Rules: Standard Slitherlink rules. Also, numbers outside the grid show the number of separate loop segments visible in that direction. A segment of length N in a given direction is taken as a building of height N. Buildings of height N block the view of all buildings behind them of equal or lesser height.

See also this example:

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 3:45, Master = 5:15, Expert = 10:30

Solution: PDF; a solution video is also available here.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

This year, we have started to have some extra difficult Sunday Stumpers, about once a month. These will be quite tough puzzles, but with a logical path to be found (and solution videos to help). This fourth Sunday Stumper is a Slitherlink puzzle with two variant rules added to it.

PDF

or solve online (using our beta test of Penpa-Edit tools; in default edgexoi mode: left-click+drag draws line, right click marks X on edge, clicking inside a cell alternates color to yellow then green then white; hitting tab will alternate to a number entry mode that can be used to write over the letter clues and hitting tab again will go back to edgexoi.)

Theme: From Here to Maternity

Author/Opus: This is the 78th puzzle from our contributing puzzlemaster John Bulten.

Rules: Standard Slitherlink rules. The letters A, M, O, and Y stand for different digits from 0 – 3. Also, an even number of cells in each row and in each column must be inside the loop.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 17:30, Master = 25:00, Expert = 50:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.