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Theme: Logical

Author/Opus: This is the 40th puzzle from our contributing puzzlemaster Palmer Mebane.

Rules: Variation of Skyscrapers. Insert a digit from 1 to 4 into each empty cell so that each row and column has one copy of each digit and exactly one mirror. Each digit in the grid represents the height of a building, and clues on the outside of the grid indicate how many buildings can be “seen” when looking from that direction, including those seen through the mirror’s reflection. Buildings block the view of any building with equal or lower height behind them.

Also see this example:

Answer String: Enter the 3rd row from left to right, followed by a comma, followed by the 4th row from left to right. Ignore the cells with the mirrors when entering the solution (i.e., just enter cells with digits 1-4).

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

Solution: PDF

Note: Follow this link for classic Skyscrapers puzzles and this link for variations on Skyscrapers puzzles. If you are new to this puzzle type, here are our easiest Skyscrapers Puzzles to get started on. More Skyscrapers puzzles can be found in The Art of Puzzles, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

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

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.

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Theme: Clue Symmetry and Logic

Author/Opus: This is the 327th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard TomTom rules, using the integers 1-8. The “rows” in this puzzle pass through opposite parallel sides of each quadrilateral; in other words, the rows bend across the surface of the apparent cube to travel in a “straight” line.

Answer String: Enter the 5th “row” from left to right followed by the 6th “row” from left to right. Separate the entries with a comma.

Time Standards (highlight to view): Grandmaster = 4:30, Master = 6:15, Expert = 12:30

Solution: PDF

Note: Follow this link for other TomTom. If you are new to this puzzle type, here are our easiest TomTom to get started on. More TomTom puzzles can be found in The Art of Puzzles, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

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Theme: Fibonacci Frame

Author/Opus: This is the 326th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard TomTom rules, using the indicated set of integers {1,1,2,3,5,8}.

Answer String: Enter the 3rd row from left to right followed by the 6th row from left to right. Separate the entries with a comma.

Time Standards (highlight to view): Grandmaster = 3:15, Master = 4:45, Expert = 9:30

Solution: PDF

Note: Follow this link for other TomTom. If you are new to this puzzle type, here are our easiest TomTom to get started on. More TomTom puzzles can be found in The Art of Puzzles, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

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or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between ship placement and shading modes. In ship placement mode, right click gives sea, left click gives circle/square, left click and drag for rounded ships.)

Theme: 1 to 4 Spiral

Author/Opus: This is the 35th puzzle from our contributing puzzlemaster Carl Worth.

Rules: Combination of Battleships and Star Battle. Follow standard Battleships rules. Also, exactly two ship segments are present in each bold region.

Answer String: For each row from top to bottom, enter the number of the first column from the left where a ship segment appears (enter just the last digit for any two-digit number). If the row is empty, enter 0. Enter these numbers as a single string with no separators.

Time Standards (highlight to view): Grandmaster = 6:00, Master = 9:00, Expert = 18:00

Solution: PDF

Note: Follow this link for classic Star Battles and this link for classic Battleships. More Battleships puzzles can be found in Battleships and Variations, in The Art of Puzzles, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

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or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between ship placement and shading modes. In ship placement mode, right click gives sea, left click gives circle/square, left click and drag for rounded ships.)

Theme: Xs Mark the Spots

Author/Opus: This is the 324th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Variation of standard Battleships rules. Instead of exterior clues, clues inside the grid indicate the number of adjacent squares, including diagonally adjacent squares, containing ship segments. Ships do not sit on cells with numbers.

Answer String: For each row from top to bottom, enter the number of the first column from the left where a ship segment appears (enter just the last digit for any two-digit number). If the row is empty, enter 0. Enter these numbers as a single string with no separators.

Time Standards (highlight to view): Grandmaster = 3:15, Master = 5:00, Expert = 10:00

Solution: PDF

Note: Follow this link for more variations on Battleships and this link for classic Battleships. More Battleships puzzles can be found in Battleships and Variations, in The Art of Puzzles, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

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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)

Theme: Clue Symmetry and Logic

Author/Opus: This is the 115th puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Variation of Castle Wall. Clue cell colors have the usual meaning. However, the numbers cannot be correct clues for any of the four directions (left, right, up, down) around the cell.

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 = 5:00, Master = 7:45, Expert = 15:30

Solution: PDF

Note: Follow this link for more Castle Wall puzzles. If you are new to this puzzle type, here are our easiest Castle Wall puzzles to get started on. More Castle Wall puzzles can be found in our beginner-friendly collection Intro to GMPuzzles as well as the larger collection Castle Wall, both by Serkan Yürekli.

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)

Theme: Clue Symmetry and Logic

Author/Opus: This is the 232nd puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Standard Castle Wall rules, but none of the clue colors are given. For each symmetric pair of clue cells, one cell is white and the other cell is black.

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 = 2:45, Master = 5:00, Expert = 10:00

Solution: PDF

Note: Follow this link for more Castle Wall puzzles. If you are new to this puzzle type, here are our easiest Castle Wall puzzles to get started on. More Castle Wall puzzles can be found in our beginner-friendly collection Intro to GMPuzzles as well as the larger collection Castle Wall, both by Serkan Yürekli.