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Theme: Pi Again (see John’s puzzle from last year)

Author/Opus: This is the 64th puzzle from our contributing puzzlemaster John Bulten.

Rules: Standard LITS rules.

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

Time Standards (highlight to view): Grandmaster = 1:40, Master = 3:14, Expert = 6:28

Solution: PDF

Note: Follow this link for other classic LITS. If you are new to this puzzle type, here are our easiest LITS to get started on. More LITS puzzles can be found in LOTS O’ LITS by Grant Fikes and Prasanna Seshadri, in The Art of Puzzles 2, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

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Theme: Logical

Author/Opus: This is the 3rd puzzle from guest contributor Yuki Kawabe.

Rules: Combination of Sundoko, Snake, and Shape puzzle styles.

Sundoko: Shade some cells to make sunglasses, consisting of a bridge (a given line, in red) and two lenses made out of orthogonally connected cells that are symmetric with respect to the perpendicular bisector of the bridge. Two lenses may not share an edge, but can intersect at a point. Cells with the bridges are not shaded, except at the bridge ends. Numbers in the grid are unshaded, and indicate the total count of unshaded cells connected vertically and horizontally to the numbered cell, including the cell itself.
Sundoko example:

Snake: Shade some cells to create a one-cell wide snake in the grid that does not cross or touch itself, not even diagonally. The snake starts and ends at the black circles and must pass through all white circles.
Snake example:

Shape: Place each of the given shapes into the grid exactly once (rotations and reflections allowed). Shapes cannot touch each other, not even diagonally.
Shape example:

SSS: In SSS, shade some cells to make sunglasses, create a single snake, and place all of the shapes in the grid. Shaded cells of different categories (sunglasses, snake, shapes) cannot share an edge. Number clues referring to unshaded cell counts consider all three categories of objects as shaded cells in this hybrid.

Or see this example:

Answer String: Enter the length in cells of each of the shaded segments (sunglasses, snake, and shapes) from left to right for the marked rows, starting at the top. Separate each row’s entry from the next with a comma.

Time Standards (highlight to view): Grandmaster = 16:00, Master = 22:00, Expert = 44:00

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

PDF

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

Theme: Grid Symmetry and Logic

Author/Opus: This is the 4th puzzle from guest contributor Takeya Saikachi.

Rules: Variation of Nanro and Nanro Signpost puzzles.

Label some cells with numbers to form a single connected group of labeled cells; no 2×2 group of cells may be fully labeled. Each bold region must contain at least one labeled cell. The small clue numbers indicate how many cells in that region are used. When two numbers are orthogonally adjacent across a region boundary, the numbers must be different. Each bolded region must be visited twice (i.e., have exactly two distinct connected groups inside it).

Also see this example:

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

Time Standards (highlight to view): Grandmaster = 5:45, Master = 7:15, Expert = 14:30

Solution: PDF

Note: Follow this link for Nanro puzzles on this website and this link for variations on Nanro puzzles. If you are new to this puzzle type, here are our easiest Nanro Puzzles to get started on. More Nanro puzzles can be found in A Number o’ Nanro by Prasanna Seshadri.

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: Logical

Author/Opus: This is the 2nd puzzle from guest contributor Yuki Kawabe.

Rules: Combination of Sundoko, Snake, and Shape puzzle styles.

Sundoko: Shade some cells to make sunglasses, consisting of a bridge (a given line, in red) and two lenses made out of orthogonally connected cells that are symmetric with respect to the perpendicular bisector of the bridge. Two lenses may not share an edge, but can intersect at a point. Cells with the bridges are not shaded, except at the bridge ends. Numbers in the grid are unshaded, and indicate the total count of unshaded cells connected vertically and horizontally to the numbered cell, including the cell itself.
Sundoko example:

Snake: Shade some cells to create a one-cell wide snake in the grid that does not cross or touch itself, not even diagonally. The snake starts and ends at the black circles and must pass through all white circles.
Snake example:

Shape: Place each of the given shapes into the grid exactly once (rotations and reflections allowed). Shapes cannot touch each other, not even diagonally.
Shape example:

SSS: In SSS, shade some cells to make sunglasses, create a single snake, and place all of the shapes in the grid. Shaded cells of different categories (sunglasses, snake, shapes) cannot share an edge. Number clues referring to unshaded cell counts consider all three categories of objects as shaded cells in this hybrid.

Or see this example:

Answer String: Enter the length in cells of each of the shaded segments (sunglasses, snake, and shapes) from left to right for the marked rows, starting at the top. Separate each row’s entry from the next with a comma.

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

Solution: PDF

PDF

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

Theme: Rectangles

Author/Opus: This is the 2nd puzzle from guest contributor Ken Endo.

Rules: Variation of Nanro and Nanro Signpost puzzles.

Label some cells with numbers to form a single connected group of labeled cells; no 2×2 group of cells may be fully labeled. Each bold region must contain at least one labeled cell. The small clue numbers indicate how many cells in that region are used. When two numbers are orthogonally adjacent across a region boundary, the numbers must be different. Each bolded region must be visited twice (i.e., have exactly two distinct connected groups inside it).

Also see this example:

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

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

Solution: PDF

Note: Follow this link for Nanro puzzles on this website and this link for variations on Nanro puzzles. If you are new to this puzzle type, here are our easiest Nanro Puzzles to get started on. More Nanro puzzles can be found in A Number o’ Nanro by Prasanna Seshadri.

PDF

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

Theme: Clue Symmetry and Logic

Author/Opus: This is the 47th puzzle from our contributing puzzlemaster Palmer Mebane.

Rules: Shade some empty cells black to create a single connected wall (the “Coral”). The shaded cells cannot form a 2×2 square anywhere in the grid, and all unshaded cells including clue cells must be connected to an edge of the grid. Clues in the gray cells indicate the lengths of the first shaded segments visible from this cell in all four directions (clues are given in ascending order). [For clarity, when considering the “first shaded segment” in a direction, gray cells see through all empty and gray cells to the edge of the grid when finding this segment, if any.]

Also see this example:

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

Time Standards (highlight to view): Grandmaster = 4:30, Master = 8:00, Expert = 16:00

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

Editorial Note: Many solvers can confuse Coral with another puzzle type with similar spelling. An easy way to remember the difference is that Cave has no R’s and also has no 2×2 Region constraint. Coral puzzles, with an R, do have this region constraint. The other general rules (about not enclosing white spaces and having a single shaded group) are shared between Cave and Coral puzzles.

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Theme: Primes

Author/Opus: This is the 125th puzzle from our contributing puzzlemaster Murat Can Tonta.

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 = 5:30, Master = 10:15, Expert = 20:30

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

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. More Nurikabe puzzles can be in The Art of Puzzles, in our beginner-friendly book Logic Puzzles 101, and in the e-book Nurikabe by Ashish Kumar.

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Theme: V

Author/Opus: This is the 8th puzzle from guest contributor Ashish Kumar.

Rules: Standard Nurikabe rules. Also, some borders are drawn in the grid between adjacent cells. One side of each border must be part of the ocean and the other side must be part of an island.

Answer String: Enter the length in cells of each of the black segments (the unnumbered, connected “ocean”) from left to right for the marked rows. Separate each row’s entry from the next with a comma.

Time Standards (highlight to view): Grandmaster = 2:45, Master = 7:30, Expert = 15:00

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. More Nurikabe puzzles can be in The Art of Puzzles, in our beginner-friendly book Logic Puzzles 101, and in the e-book Nurikabe by Ashish Kumar.

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Theme: 1 to 9 (Originally on 2018 Puzzle Grand Prix Round 3)

Author/Opus: This is the 7th puzzle from guest contributor Ashish Kumar.

Rules: Standard Nurikabe rules. Also, the numbers outside the grid show the number of shaded segments visible in that direction (as in Skyscrapers). A shaded segment of length N in a given direction is taken as a building of height N. A building blocks the view of any building behind it of equal or lesser height. For instance, in the example, there are 3 buildings seen in the fourth row from the left (as 1 < 2 < 3) but only 1 building seen in the third row from the right (as 3 > 2).

Answer String: Enter the length in cells of each of the black segments (the unnumbered, connected “ocean”) from left to right for the marked rows. Separate each row’s entry from the next with a comma.

Time Standards (highlight to view): Grandmaster = 1:45, Master = 4:30, Expert = 9:00

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. More Nurikabe puzzles can be in The Art of Puzzles, in our beginner-friendly book Logic Puzzles 101, and in the e-book Nurikabe by Ashish Kumar.

PDF

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

Theme: Logical

Author/Opus: This is the 286th puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Standard Nurikabe rules.

Answer String: Enter the length in cells of each of the black segments (the unnumbered, connected “ocean”) from left to right for the marked rows. Separate each row’s entry from the next with a comma.

Time Standards (highlight to view): Grandmaster = 2:00, Master = 3:00, Expert = 6:00

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

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. More Nurikabe puzzles can be in The Art of Puzzles, in our beginner-friendly book Logic Puzzles 101, and in the e-book Nurikabe by Ashish Kumar.