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.

Our most recent week of Slitherlink puzzles are gathered in this PDF and the solutions are in this PDF. We will have a challenging Sunday Stumper up soon by Matej Uher, and this week also marks the release of Slitherlink and Variations 2, a new e-book also by Matej Uher with 30 classic Slitherlink (including 1 giant) and 22 variations across 6 styles. Check out our store for details on all our Slitherlink collections.

The daily solution videos are on the posts and linked below:

We’ve also recently uploaded a new version of Penpa-Edit (from 2.26.18 to 3.0.3) with several quality of life improvements. A big one (that we will highlight again in the future when we have an appropriate week) is that coloring of regions now works like drawing region boundaries for solution checking purposes in Fillomino, Pentominous, Araf, and other puzzles. As long as everything is colored (i.e., not white) and edge-adjacent regions are a different color, they are marked as implicit edges and compatible with checking. This update also includes some improvements to the top interface sizing that maintains the size (rather than moving up and down) when shifting between tools, better keyboard support for Sudoku movement in hex/cube modes, and several others described in the change history. Thanks to Swaroop and the other developers for these improvements.

This next week will feature LITS puzzles.

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: Columns

Author/Opus: This is the 11th puzzle from guest contributor Michael Tang.

Rules: Standard Slitherlink rules.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 5:15, Expert = 10:30

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: Pairs

Author/Opus: This is the 11th puzzle from guest contributor Eric Fox.

Rules: Standard Slitherlink rules.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:30, Master = 2:00, Expert = 4:00

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: Antisymmetry

Author/Opus: This is the 383rd puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Standard Slitherlink rules.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:15, Master = 1:40, Expert = 3:20

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: 2×2

Author/Opus: This is the 98th puzzle from our contributing puzzlemaster Ashish Kumar.

Rules: Standard Slitherlink rules.

Difficulty: 1 star

Time Standards (highlight to view): Grandmaster = 0:30, Master = 0:45, Expert = 1:30

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 week we crossed a milestone with over 2,500 puzzles posted on the web. Alongside this huge number, which has still never included a broken puzzle with 0 or more than 1 solutions, we finished posting solution PDFs for all of our earliest puzzles from 2013 so every web week now has solutions available. We also now have Penpa versions for almost every major style (2350+ puzzles) and mainly have one-off variations to still digitize. So by the time we hit our 10-year anniversary at the end of this year, our archive will be in great shape! If you’ve appreciated our content through the years, please consider buying some of our books (all with original puzzles) or making a donation to help support the site and our authors.

6 of our 2,500+ puzzles coming from this past week, which featured the number placement styles Smashed Sums and Terra X, are gathered in this PDF and the solutions are in this PDF.

The daily solution videos are on the posts and linked below:

This next week will feature Slitherlink and variations, including a Sunday Stumper in one week’s time. Next Sunday we will also be releasing the new book Slitherlink and Variations 2 by Matej Uher, so look forward to a week+ of getting thrown for a loop.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)

Theme: Mystery Box

Author/Opus: This is the 12th puzzle from guest contributor Sam Cappleman-Lynes.

Rules: Place a number from 0 to 9 into each area so that no two areas that touch orthogonally share the same number. Wherever four areas meet at a point (marked with dots as a visual aid), the numbers in those areas must add up to 10.

Also, see this example:

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 14:45, Master = 21:00, Expert = 42:00

Solution: PDF and solving video.

Note: Follow this link for other less common Number Placement puzzles.