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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: Think Positive (there are no zero clues)

Author/Opus: This is the 164th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Combination of Slitherlink and Masyu rules.

Specifically, draw a single closed loop by connecting neighboring dots horizontally or vertically so that each number represents the number of adjacent edges used by the loop. The loop passes through all large circles. It must go straight through the white circles with at least one side turning at the next dot; it must turn at the black circles and then go straight through the next dot in both directions.

Answer String: Enter the length in cells of each of the internal loop segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

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

Solution: PDF

Note: Follow these links for other Slitherlink variations and Masyu variations. Or follow these links for classic Slitherlink and classic Masyu puzzles.

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: Symmetry and Logic

Author/Opus: This is the 4th puzzle from guest contributor Hans van Stippent (who has also contributed these three Sunday Surprises).

Rules: Standard Slitherlink rules. Also, there are some sheep (marked S) that must be inside the loop and some wolves (marked W) that must be outside the loop.

Answer String: Enter the length in cells of each of the internal loop segments following the arrows for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 2:45, Master = 5:00, Expert = 10:00

Solution: PDF; a solution video is available here.

Note: Follow this link for other Slitherlink variations and this link for classic Slitherlink. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on.

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

Theme: Clue symmetry and logic

Author/Opus: This is the 32nd puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Variation of Masyu rules. In addition to the standard rules, some white circles may be shaded to become black circles.

Answer String: Enter the length in cells of the horizontal loop segments from left to right in the marked rows, starting at the top. If the loop only has vertical segments in the marked row, enter 0. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 3:00, Master = 3:45, Expert = 7:30

Solution: PDF

Note: Follow this link for other Masyu variations and this link for classic Masyu. If you are new to this puzzle type, here are our easiest Masyu to get started on.

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: Quadrants

Author/Opus: This is the 14th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Combination of Slitherlink and Masyu rules.

Specifically, draw a single closed loop by connecting neighboring dots horizontally or vertically so that each number represents the number of adjacent edges used by the loop. The loop passes through all large circles. It must go straight through the white circles with at least one side turning at the next dot; it must turn at the black circles and then go straight through the next dot in both directions.

Answer String: Enter the length in cells of each of the internal loop segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 1:40, Master = 2:30, Expert = 5:00

Solution: PDF

Note: Follow these links for other Slitherlink variations and Masyu variations. Or follow these links for classic Slitherlink and classic Masyu puzzles.

View image directly for larger form.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: The Magic of 23

Author/Opus: This is the 31st puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: In this variation of Nurikabe, the no 2×2 ocean rule is removed and instead all ocean cells must belong to a single closed loop.

Specifically: Divide the grid into regions called “islands”, each containing exactly one of the given numbers and with the same area as that number. Islands can only touch diagonally. A single closed loop (without intersection or crossings) must be drawn in all remaining cells.

Answer String: Enter the length in cells of the horizontal loop segments from left to right in the marked rows, starting at the top. If the loop only has vertical segments in the marked row, enter 0. Separate each row’s entry with a comma. This example has the key “12,3”.

Time Standards (highlight to view): Grandmaster = 4:45, Master = 6:30, Expert = 13:00

Solution: PDF

Note: Follow this link for classic Nurikabe puzzles on this website and this link for other variations on Nurikabe puzzles. If you are new to this puzzle type, here are our easiest Nurikabe puzzles to get started on.

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Theme: An Odd Introduction

Author/Opus: This is the 30th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: In this variation of Nurikabe, the no 2×2 ocean rule is removed and instead all ocean cells must belong to a single closed loop.

Specifically: Divide the grid into regions called “islands”, each containing exactly one of the given numbers and with the same area as that number. Islands can only touch diagonally. A single closed loop (without intersection or crossings) must be drawn in all remaining cells.

Answer String: Enter the length in cells of the horizontal loop segments from left to right in the marked rows, starting at the top. If the loop only has vertical segments in the marked row, enter 0. Separate each row’s entry with a comma. This example has the key “12,3”.

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

Solution: PDF

Note: Follow this link for classic Nurikabe puzzles on this website and this link for other variations on Nurikabe puzzles. If you are new to this puzzle type, here are our easiest Nurikabe puzzles to get started on.

(view image directly for a larger form)

PDF

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

Theme: Triple Threat

Author/Opus: This is the 28th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: In this variation of Tapa, the wall is in the form of a single non-intersecting loop. Clues inside the grid represent the number of neighboring cells visited by the loop; if there is more than one number in a cell, each number should be represented with a separate loop segment. There is no 2×2 rule of Tapa in this puzzle. This example image should help:

Answer String: Enter the length in cells of the horizontal loop segments from left to right in the marked rows, starting at the top. Separate each row’s entry with a comma. For the example, this would be “11,12”.

Time Standards (highlight to view): Grandmaster = 8:15, Master = 10:00, Expert = 20:00

Solution: PDF

Note: Follow this link for other Tapa-Like Loop puzzles. If you are new to this puzzle type, here are our easiest Tapa puzzles to get started on.

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

Theme: Double Trouble

Author/Opus: This is the 11th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: In this variation of Tapa, the wall is in the form of a single non-intersecting loop. Clues inside the grid represent the number of neighboring cells visited by the loop; if there is more than one number in a cell, each number should be represented with a separate loop segment. There is no 2×2 rule of Tapa in this puzzle. This example image should help:

Answer String: Enter the length in cells of the horizontal loop segments from left to right in the marked rows, starting at the top. Separate each row’s entry with a comma. For the example, this would be “11,12”.

Time Standards (highlight to view): Grandmaster = 1:45, Master = 2:45, Expert = 5:30

Solution: PDF

Note: Follow this link for other Tapa-Like Loop puzzles. If you are new to this puzzle type, here are our easiest Tapa puzzles to get started on.

PDF

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

Theme: Clue Symmetry and Logic

Author/Opus: This is the 85th puzzle from our contributing puzzlemaster Grant Fikes.

Rules: In this variation of Tapa, the wall is in the form of a single non-intersecting loop. Clues inside the grid represent the number of neighboring cells visited by the loop; if there is more than one number in a cell, each number should be represented with a separate loop segment. There is no 2×2 rule of Tapa in this puzzle. This example image should help:

Answer String: Enter the length in cells of the horizontal loop segments from left to right in the marked rows, starting at the top. Separate each row’s entry with a comma. For the example, this would be “11,12”.

Time Standards (highlight to view): Grandmaster = 1:20, Master = 2:15, Expert = 4:30

Solution: PDF

Note: Follow this link for other Tapa-Like Loop puzzles. If you are new to this puzzle type, here are our easiest Tapa puzzles to get started on.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

Theme: Even Slashes

Author/Opus: This is the 156th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Variation of Cave rules. Each clue represents the product of the # of row cells visible (including the cell itself) with the # of column cells visible (including the cell itself).

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 7:30, Master = 13:30, Expert = 27:00

Solution: PDF

Note: Follow this link for other Cave variations and this link for other classic Caves. If you are new to this puzzle type, here are our easiest Cave Puzzles to get started on.