This Rossini Sudoku was originally written by Ashish Kumar for the 16th World Sudoku Championship, but it proved a bit too difficult for what we needed in the championship. So we kept it to be a Sunday Special on GMPuzzles, where we expect this puzzle works perfectly for solvers looking for a challenge.

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Theme: Ribbon

Author/Opus: This is the 119th puzzle from our contributing puzzlemaster Ashish Kumar.

Rules: Standard Sudoku rules. Also, arrows outside the grid indicate if the first three numbers are in ascending or descending order. The arrow points towards the highest number in the series. If no arrows outside the grid are given, the first three numbers can be in neither ascending nor descending order.

See also this example:

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 8:30, Master = 17:45, Expert = 35:30

Solution: PDF and solving animation.

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.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Season 2 Preview Week Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access and check subscriber instructions for role-related access.

The last two closing puzzles of the World Sudoku Championship playoffs were very tricky, starting with this hybrid of Clone and Shape Sudoku by Joseph Howard.

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Theme: 8 Rings

Author/Opus: This is the 33rd puzzle from guest contributor Joseph Howard.

Rules: Combination of Shape and Clone Sudoku rules. Insert a number from 1 to 9 into each cell so that no number repeats in any row, column, or bold region. Also, there are some numbered shapes that must be put into the grid. Shapes can be rotated, but cannot be reflected. Each shape outside the grid must appear exactly once inside the grid. Also, all remaining shaded regions of the same shape (“clones”) must be able to be paired together to include the same numbers in the same positions.

Estimated Difficulty: 3.5 stars

Solution: PDF for all playoff puzzles.

Note: Follow this link for more variations of Sudoku.

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.