Killer Sudoku by Grant Fikes

Killer Sudoku by Grant Fikes

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Theme: Clue Symmetry and Logic

Author/Opus: This is the 290th puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Standard Sudoku rules. Also, the sum of the digits in each cage must equal the value given in the upper-left corner of that cage. Digits cannot repeat inside a cage.

Answer String: Enter the 2nd row from left to right, followed by a comma, followed by the 5th row from left to right.

Time Standards (highlight to view): Grandmaster = 9:00, Master = 15:00, Expert = 30:00

Solution: PDF

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

XV Sudoku by Ashish Kumar

XV Sudoku by Ashish Kumar

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Theme: Clue Symmetry and Logic

Author/Opus: This is the 10th puzzle from guest contributor Ashish Kumar.

Rules: Standard Sudoku rules. Also, whenever the numbers in two adjacent cells sum to exactly 10 or 5, an X or V is placed on the edge between cells reflecting the Roman numerals for 10 or 5. All adjacent cells not marked with an X or V cannot add up to 10 or 5.

Answer String: Enter the 6th row from left to right, followed by a comma, followed by the 9th row from left to right.

Time Standards (highlight to view): Grandmaster = 8:30, Master = 15:00, Expert = 30:00

Solution: PDF

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

Spiral Galaxies by Grant Fikes

Spiral Galaxies by Grant Fikes

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Theme: Something Meta?

Author/Opus: This is the 289th puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Standard Spiral Galaxies rules (treat white and black circles the same when solving). After completing the grid, there is a secret message to find.

Answer String: Enter the hidden word in ALL CAPITAL LETTERS.

Time Standards (highlight to view): Grandmaster = 20:00, Master = 30:00, Expert = 60:00

Solution: PDF

Note: Follow this link for classic Spiral Galaxies puzzles on this website and this link for variations on Spiral Galaxies puzzles. If you are new to this puzzle type, here are our easiest Spiral Galaxies Puzzles to get started on. More Spiral Galaxies puzzles can be found in The Art of Puzzles 2.

Galactic Fillomino by Carl Worth

Galactic Fillomino by Carl Worth

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or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a composite mode for line/edge drawing and a number entry mode.)

Theme: Clue Symmetry and Logic

Author/Opus: This is the 36th puzzle from our contributing puzzlemaster Carl Worth.

Rules: Combination of Spiral Galaxies and Fillomino rules. Divide the grid along the dotted lines into regions, each of which must contain either exactly one circle, or one or more identical given numbers. (Note that there are no “hidden polyominoes” in this puzzle meaning there are no regions without a given number or a given circle.) Each region containing a circle is a “galaxy” and must have rotational symmetry with the circle at its center. Each region with given numbers must be the same size in cells as those numbers. Two regions with numbers of the same size cannot share an edge, but a region with numbers and a region with a circle in it can be the same size.

Answer String: For each cell in the marked rows, enter the area of the region it belongs to. Enter just the last digit for any two-digit number. Start with the 4th row, followed by a comma, followed by the 8th row.

Time Standards (highlight to view): Grandmaster = 7:00, Master = 13:45, Expert = 27:30

Solution: PDF

Note: Follow this link for classic Spiral Galaxies puzzles on this website and this link for variations on Spiral Galaxies puzzles. If you are new to this puzzle type, here are our easiest Spiral Galaxies Puzzles to get started on. More Spiral Galaxies puzzles can be found in The Art of Puzzles 2.

Skyscrapers (with Sum Baskets) by Palmer Mebane

Skyscrapers (with Sum Baskets) by Palmer Mebane

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Theme: Fours and Fives

Author/Opus: This is the 48th puzzle from our contributing puzzlemaster Palmer Mebane.

Rules: Standard Skyscrapers rules (using digits 1 to 7). Also, there are some regions (”Sum baskets”) in the grid marked by dashed lines. The sum of the buildings in these sum baskets is given. Building heights can repeat within a basket.

Answer String: Enter the 1st row from left to right, followed by a comma, followed by the 7th row from left to right.

Time Standards (highlight to view): Grandmaster = 4:15, Master = 6:30, Expert = 13:00

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.

Inner Coral by Palmer Mebane

Inner Coral by Palmer Mebane

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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:

Inner Coral Example by Thomas Snyder

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.

Nurikabe Loop by Murat Can Tonta

Nurikabe by Murat Can Tonta

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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.

Nurikabe Loop by Serkan Yürekli

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.

Nurikabe (Borders) by Ashish Kumar

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.

Nurikabe Skyscrapers by Thomas Snyder

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.

TomTom by Murat Can Tonta

TomTom by Murat Can Tonta

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Theme: Clue Symmetry and Logic

Author/Opus: This is the 123rd puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Standard TomTom rules, using the integers 1-8.

Answer String: Enter the 5th row from left to right followed by the 8th row from left to right. Separate the entries with a comma.

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

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.

TomTom (Isometric) by Thomas Snyder

TomTom by Thomas Snyder

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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.