### Sunday Stumper: Yajilin by Sam Cappleman-Lynes

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 twelfth Sunday Stumper of 2022 is a Yajilin puzzle by Sam Cappleman-Lynes with a tricky path into and out from the “Open Middle”.

(view directly for a larger image)

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Theme: Open Middle

Author/Opus: This is the 13th puzzle from guest contributor Sam Cappleman-Lynes.

Rules: Standard Yajilin rules.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 8:30, Master = 12:30, Expert = 25:00

Solution: PDF and solving video.

Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.

### Yajilin by David Altizio

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Theme: 4×4 Grid

Author/Opus: This is the 11th puzzle from guest contributor David Altizio.

Rules: Standard Yajilin rules.

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 7:00, Master = 9:45, Expert = 19:30

Solution: PDF and solving video.

Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.

### Yajilin by JinHoo Ahn

(view directly for a larger image)

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Theme: Parallel Lines

Author/Opus: This is the 61st puzzle from our contributing puzzlemaster JinHoo Ahn.

Rules: Standard Yajilin rules.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 6:00, Master = 7:30, Expert = 15:00

Solution: PDF and solving video.

Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.

### Yajilin (Even Rows/Columns) by Grant Fikes

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Theme: Fortysomething?

Author/Opus: This is the 393rd puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Standard Yajilin rules. Also, an even number of cells must be shaded in each row and in each column.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 3:15, Master = 4:15, Expert = 8:30

Solution: PDF and solving video.

Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.

### Yajilin (Masyu) by Chandrachud Nanduri

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Theme: Divided by 1

Author/Opus: This is the 2nd puzzle from guest contributor Chandrachud Nanduri.

Rules: Standard Yajilin rules. Also, the loop must go straight through the cells with white circles, with a turn in at least one of the cells immediately before/after each white circle. The loop must make a turn in all the black circles, but must go straight in both cells immediately before/after each black circle.

Difficulty: 2.5 stars

Time Standards (highlight to view): Grandmaster = 2:00, Master = 3:30, Expert = 7:00

Solution: PDF and solving video.

Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.

### Yajilin by wormsofcan

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Theme: Windmill

Author/Opus: This is the 9th puzzle from guest contributor wormsofcan.

Rules: Standard Yajilin rules.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:15, Master = 2:30, Expert = 5:00

Solution: PDF and solving video.

Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.

### Yajilin by Mark Sweep

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Theme: One Up Two Down

Author/Opus: This is the 9th puzzle from guest contributor Mark Sweep.

Rules: Standard Yajilin rules.

Difficulty: 1.5 stars

Time Standards (highlight to view): Grandmaster = 1:00, Master = 1:45, Expert = 3:30

Solution: PDF and solving video.

Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.

### Yajilin by Serkan Yürekli

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Theme: Valentines

Author/Opus: This is the 367th puzzle from our managing editor Serkan Yürekli.

Rules: Standard Yajilin rules.

Difficulty: 1.5 stars

Time Standards (highlight to view): Grandmaster = 0:45, Master = 1:20, Expert = 2:40

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

Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.

### Yajilin by Murat Can Tonta

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Theme: Welcome to 2022

Author/Opus: This is the 217th puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Standard Yajilin rules.

Difficulty: 1 star

Time Standards (highlight to view): Grandmaster = 0:40, Master = 1:15, Expert = 2:30

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

Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.

### Yajilin (Castle Wall) by Thomas Snyder

See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Author/Opus: This is the 401st* puzzle from Thomas Snyder, aka Dr. Sudoku (*the 400th puzzle opus number is being held for an upcoming post).

Rules: Standard Yajilin rules: Blacken some white cells and then draw a single closed loop (without intersections or crossings) through all remaining white cells. Blackened cells cannot share an edge with each other. Some cells are outlined and in gray and cannot be part of the loop. Numbered arrows in such cells indicate the total number of blackened cells that exist in that direction in the grid.

Also, in addition to the usual gray clues, some clues are white and black and act similarly to Castle Wall clues. White clues must be inside the loop and black clues must be outside the loop. White and black clues indicate the sum of the lengths of loop segments in the indicated direction.

Difficulty: 2.5 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF