PDF

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

Theme: Square Knots

Author/Opus: This is the 2nd puzzle from guest contributor Michael Rios.

Rules: Standard Sudoku rules. Also, some arrow shapes are in the grid; the sum of the numbers along the path of each arrow must equal the number in the circled cell (numbers can repeat on an arrow). Some cages are in the grid marked by dashed lines; the sum of the numbers in these cages must equal the value given in the upper-left corner of that cage (numbers cannot repeat inside a cage). Some dots are given between two cells; a white dot shows that the numbers in those cells are consecutive and a black dot shows that the number in one of the cells has twice the value of the other (adjacent cells without dots may or may not follow these rules). Finally, some thermometer shapes are in the grid; the numbers along the thermometer must be strictly increasing from the round bulb to the flat end.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 10:45, Master = 18:45, Expert = 37:30

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

Note: Follow this link for more Arrow Sudoku. Follow this link for more Thermo-Sudoku puzzles. More Arrow and Thermo-Sudoku puzzles can be found in The Art of Sudoku 2. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.

PDF

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

Theme: Plus and Minuses

Author/Opus: This is the 1st puzzle from guest contributor Michael Rios.

Rules: Standard Sudoku rules. Also, each row, column and bold region must contain two negative numbers. The sum of the positive and negative numbers in each cage must equal the value given in the upper-left corner of that cage. Numbers (ignoring sign) cannot repeat inside a cage.

See also this example:

Difficulty: 5 stars

Time Standards (highlight to view): Grandmaster = 15:30, Master = 26:00, Expert = 52:00

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

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Sudoku puzzles can be found in The Art of Sudoku, The Art of Sudoku 2 and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

Here is a (very hard) sample puzzle from the Killer Sudoku puzzle pack by Serkan Yürekli, which was just added to our e-store.

PDF

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

Theme: Time Killer

Author/Opus: This puzzle comes from our managing editor Serkan Yürekli as part of his new e-book.

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

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 11:00, Master = 24:00, Expert = 48:00

Solution: PDF; a solution video from Cracking the Cryptic will be available here.

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.

PDF

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

Theme: Initial Impressions

Author/Opus: This is the 331st puzzle from our contributing puzzlemaster Grant Fikes.

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

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:45, Master = 7:30, Expert = 15:00

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

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.

PDF

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

Theme: Stuck Z

Author/Opus: This is the 319th puzzle from our contributing puzzlemaster Grant Fikes.

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

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:00, Master = 6:15, Expert = 12:30

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

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.

PDF

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

Theme: Rocket Launch

Author/Opus: This is the 248th puzzle from our contributing puzzlemaster Serkan Yürekli.

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

Answer String: Enter the 2nd row from left to right, followed by a comma, followed by the 8th row from left to right.

Time Standards (highlight to view): Grandmaster = 4:00, Master = 7:30, Expert = 15:00

Solution: PDF

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.

PDF

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

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 numbers in each cage must equal the value given in the upper-left corner of that cage. Numbers 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.

PDF

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

Theme: Clue Symmetry and Logic (Originally on 2017 Brand’s Sudoku Open)

Author/Opus: This is the 168th puzzle from our contributing puzzlemaster Serkan Yürekli.

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

Answer String: Enter the 3rd 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 = 12:00, Expert = 24:00

Solution: PDF; a solution video is available here.

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.

PDF

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

Theme: Fan (for Randy Rogers)

Author/Opus: This is the 156th puzzle from our contributing puzzlemaster Serkan Yürekli.

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

Answer String: Enter the 5th row from left to right, followed by a comma, followed by the 9th row from left to right.

Time Standards (highlight to view): Grandmaster = 6:45, Master = 16:00, Expert = 32:00

Solution: PDF

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.

PDF

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

Theme: Clue Symmetry and Logic

Author/Opus: This is the 231st puzzle from our contributing puzzlemaster Grant Fikes.

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

Answer String: Enter the 8th row from left to right, followed by a comma, followed by the 7th column from top to bottom.

Time Standards (highlight to view): Grandmaster = 3:45, Master = 5:30, Expert = 11:00

Solution: PDF

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.