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Theme: Boxing Day

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

Rules: Standard Even/Odd Sudoku rules (i.e., cells with a square contain an even digit; cells with a circle contain an odd digit).

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 = 3:15, Master = 5:30, Expert = 11:00

Solution: PDF

Note: Follow this link for more Even/Odd Sudoku puzzles. If you are new to this puzzle type, here are our easiest Even/Odd Sudoku to get started on. More Even/Odd Sudoku puzzles can be found in The Art of Sudoku 2.

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

Theme: Clueless

Author/Opus: This is the 6th puzzle from guest contributor Ashish Kumar.

Rules: Standard Thermo-Sudoku rules.

Answer String: Enter the 5th row from left to right, followed by a comma, followed by the 7th row from left to right.

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

Solution: PDF

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2.

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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: Propeller

Author/Opus: This is the 5th puzzle from guest contributor Ashish Kumar.

Rules: Standard Cave rules.

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 = 4:00, Master = 7:15, Expert = 14:30

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

Note: Follow this link for other classic Caves. If you are new to this puzzle type, here are our easiest Cave Puzzles to get started on. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.

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Theme: Diagonals

Author/Opus: This is the 4th puzzle from guest contributor Ashish Kumar.

Rules: Standard Even/Odd Sudoku rules (i.e., cells with a square contain an even digit; cells with a circle contain an odd digit).

Answer String: Enter the 4th row from left to right, followed by a comma, followed by the 7th row from left to right.

Time Standards (highlight to view): Grandmaster = 5:45, Master = 8:00, Expert = 16:00

Solution: PDF

Note: Follow this link for more Even/Odd Sudoku puzzles. If you are new to this puzzle type, here are our easiest Even/Odd Sudoku to get started on. More Even/Odd Sudoku puzzles can be found in The Art of Sudoku 2.

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: Clue Symmetry and Logic

Author/Opus: This is the 3rd puzzle from guest contributor Ashish Kumar.

Rules: Standard Cave rules.

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 = 2:00, Master = 3:30, Expert = 7:00

Solution: PDF

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

PDF

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

Theme: Level Thermometers

Author/Opus: This is the 2nd puzzle from guest contributor Ashish Kumar.

Rules: Standard Thermo-Sudoku rules.

Answer String: Enter the 2nd column from top to bottom, followed by a comma, followed by the 8th column from top to bottom.

Time Standards (highlight to view): Grandmaster = 3:00, Master = 5:30, Expert = 11:00

Solution: PDF

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2.

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: Logical

Author/Opus: This is the 1st puzzle from guest contributor Ashish Kumar.

Rules: Locate a snake of unknown length in the grid, whose head, tail, and exact center are given. The snake does not touch itself, even diagonally. Numbers outside the grid indicate the number of snake cells in that row/column.
See also this example:

Answer String: Enter the length in cells of each of the snake segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma. This example has the key “211,31”.

Time Standards (highlight to view): Grandmaster = 4:00, Master = 9:30, Expert = 19:00

Solution: PDF