This week we are sharing the 10 puzzles that decided the World Sudoku Championship this year. There was an individual and a team round focusing on “Clone” puzzles, and the fifth playoff puzzle was such a Clone Sudoku with a Noughts and Crosses theme.

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Theme: Noughts and Crosses

Author/Opus: This is the 413th puzzle from our managing editor Serkan Yürekli.

Rules: Standard Sudoku rules. Also, all shaded regions of the same shape (“clones”) must include the same numbers in the same positions. Numbers may repeat within a clone.

Estimated Difficulty: 3 stars

Solution: PDF for all playoff puzzles.

Note: Follow this link for more variations of Sudoku.

The fourth World Sudoku Championship playoff puzzle was this Diagonal Sudoku from Thomas Snyder with a “16” theme. All the playoff puzzles represented different themed sudoku rounds and this one represented the Extra Toppings round with extra-region-type constraints.

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Theme: 16th WSC

Author/Opus: This is the 454th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules. Also, numbers cannot repeat on the marked diagonals.

Estimated Difficulty: 2.5-3 stars

Solution: PDF for all playoff puzzles.

Note: Follow this link for more variations of Sudoku.

[This puzzle comes from the 2022 US Sudoku Grand Prix round. Multiples Sudoku was a basic idea I had not seen before in a number placement puzzle, so I decided to use it in this competition structure taking full advantage of the limitations with putting so many eight clues into the grid. It ended up being the hardest puzzle in the competition, but without given numbers I’m not sure there are any “easy” Multiples Sudoku to really construct for solvers.]

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Theme: Too Many Eights?

Author/Opus: This is the 443rd puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules. Also, some numbers are given on the edges between two adjacent cells. Treating those cells as a two-digit number (reading left to right or top to bottom), the two-digit number must be a multiple of the clue. (For example, near a 7 clue, the two digits can be 14, 21, 28, 35, ….)

Estimated Difficulty: 4 stars

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.

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Theme: Downward Spiral

Author/Opus: This is the 429th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules: Insert a number from 1 to 9 into each cell so that no number repeats in any row, column, or bold region.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 4:15, Master = 5:45, Expert = 11:30

Solution: PDF and solving video.

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

This variation from Dr. Sudoku will appear on the 8th round of the Sudoku Grand Prix opening August 5th and running through August 8th. This puzzle was created as the “example” puzzle for the style, and is a representative puzzle (in difficulty and style) to help prepare for the competition.

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Theme: Boxes

Author/Opus: This is the 417th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules. Also, some numbers are given on the edges between two adjacent cells. Treating those cells as a two-digit number (reading left to right or top to bottom), the two-digit number must be a multiple of the clue. (For example, near a 7 clue, the two digits can be 14, 21, 28, 35, ….)

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 7:30, Master = 10:00, Expert = 20:00

Solution: PDF and solving video.

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.

(view directly for a larger image)

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Theme: Even/Odd Trios

Author/Opus: This is the 235th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Sudoku rules. Numbers do not repeat along any of the three directions in which the hexagonal cells share edges.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 2:00, Master = 2:45, Expert = 5:30

Solution: PDF and solving video.

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

This year, we started posting some extra difficult Sunday Stumpers, about once a month. These will be quite tough puzzles, but with a logical path to be found (and solution videos to help). This eleventh Sunday Stumper is a challenging (anti-)XV Sudoku by Murat Can Tonta.

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Theme: Pairs

Author/Opus: This is the 214th puzzle from our contributing puzzlemaster Murat Can Tonta.

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.

Difficulty: 5 stars

Time Standards (highlight to view): Grandmaster = 17:30, Master = 30:00, Expert = 1:00:00

Solution: PDF; a solution video is also 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.

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Author/Opus: This is the 212th puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Standard Sudoku rules. Also, numbers cannot repeat in any cells separated by a chess knight’s move.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 3:30, Master = 9:00, Expert = 18:00

Solution: PDF; a solution video is also 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.

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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.

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Theme: Tau Cross

Author/Opus: This is the 79th puzzle from our contributing puzzlemaster John Bulten.

Rules: Standard Sudoku rules. Also, standard Skyscrapers rules.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 8:00, Master = 14:00, Expert = 28:00

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

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, in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli, and in the e-book Skyscrapers by Ashish Kumar.