Archive for the ‘Variation’ Category:

Sunday Special: Rossini Sudoku by Ashish Kumar

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.

Rossini Sudoku by Ashish Kumar

PDF

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

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:

Rossini Sudoku Example by Ashish Kumar

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.

Star Battle (Hidden Double) by Takeya Saikachi

It seems amazing that Sagittarius A, a black hole, lies at the center of our galaxy, so one may wonder where Takeya Saikachi’s design breaks apart from other unusual stellar possibilities.

Star Battle (Hidden Double) by Takeya Saikachi

PDF

or solve online (using our beta test of Penpa-Edit tools with Double Minesweeper mines standing for stars. Left clicking a cell places a star, left clicking a cell again places a second star. Right clicking a cell marks it empty with a cross, right clicking between cells places a dot for notation.)

Author/Opus: This is the 36th puzzle from our contributing puzzlemaster Takeya Saikachi.

Rules: Variation of Star Battle rules. There are three stars per row, column, and region. Cells with stars can contain either 1 or 2 stars, but stars can still not be placed in adjacent cells that share an edge or corner.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 4:15, Master = 5:15, Expert = 10:30

Solution: PDF and solving animation.

Note: Follow this link for other classic Star Battles and this link for Star Battle variations. If you are new to this puzzle type, here are our easiest Star Battles to get started on. More Star Battle puzzles can be found in The Art of Puzzles, in the books Star Battle by JinHoo Ahn and Star Battle 2 by JinHoo Ahn and Murat Can Tonta, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

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.

Star Battle (Hidden Double) by Serkan Yürekli

Since we, as solvers, prefer to focus on the small regions of a Star Battle, Serkan Yürekli’s grid may allow us to continue thinking that way as we look for the hidden doubles.

Star Battle (Hidden Double) by Serkan Yürekli

PDF

or solve online (using our beta test of Penpa-Edit tools with Double Minesweeper mines standing for stars. Left clicking a cell places a star, left clicking a cell again places a second star. Right clicking a cell marks it empty with a cross, right clicking between cells places a dot for notation.)

Author/Opus: This is the 422nd puzzle from our managing editor Serkan Yürekli.

Rules: Variation of Star Battle rules. There are three stars per row, column, and region. Cells with stars can contain either 1 or 2 stars, but stars can still not be placed in adjacent cells that share an edge or corner.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:45, Master = 2:45, Expert = 5:30

Solution: PDF and solving animation.

Note: Follow this link for other classic Star Battles and this link for Star Battle variations. If you are new to this puzzle type, here are our easiest Star Battles to get started on. More Star Battle puzzles can be found in The Art of Puzzles, in the books Star Battle by JinHoo Ahn and Star Battle 2 by JinHoo Ahn and Murat Can Tonta, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

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.

WPC Loop/Path Mini-Playoff 3/3: Cross Border Parity Loop by Craig Kasper

The last Loop/Path puzzle is one of the “new” styles that debuted in the Breadth of America loop variety round, a Cross Border Parity Loop by Craig Kasper. (We expect this puzzle to be much harder for those who didn’t solve the three competition puzzles that preceded it.)

Cross Border Parity Loop by Craig Kasper

PDF

or solve online (using our beta test of Penpa-Edit tools in linex mode where left click+drag draws lines and right click marks X’s; use tab to alternate to a shading mode to mark the loop states)

Author/Opus: This is the 9th puzzle from guest contributor Craig Kasper.

Rules: Draw a single, non-intersecting loop that has two states, which are white and black. The puzzle grid has heavily shaded borders, which define areas in the grid. Whenever the loop crosses a border (including borders inside an area), it changes state from white to black or from black to white. A black circled clue provides the number of cells in each area that the loop traverses in the black state, and a white circled clue provides the number of cells in each area that the loop traverses in the white state. Each “?” represents an unknown integer, zero or larger.

See also this example:

Cross Border Parity Loop by Craig Kasper

Estimated Difficulty: 2.5-3 stars

Solution: PDF for all Loop/Path playoff puzzles.

Note: Follow this link for other uncommon Loop/Path puzzles.

WPC Loop/Path Mini-Playoff 2/3: Slitherlink by Serkan Yürekli

The next Loop/Path puzzle, reflecting an unusual grid geometry round, is this “Trophy” Slitherlink by Serkan Yürekli. Can you figure out how all the unusual parts of the grid will mark the 30th World Puzzle Championship.

Slitherlink by Serkan Yürekli

PDF

Author/Opus: This is the 415th puzzle from our managing editor Serkan Yürekli.

Rules: Variation of Slitherlink rules. Draw a single, non-intersecting loop on an irregular grid that can only follow the lines between the dots. Numbers inside a cell indicate how many of the edges of that cell are part of the loop.

Estimated Difficulty: 2 stars

Solution: PDF for all Loop/Path playoff puzzles.

Note: Follow this link for other classic Slitherlink. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in our books The Art of Puzzles and Slitherlink and Variations.

WPC Number Placement Mini-Playoff 3/3: Skyscrapers (Gap) by David Altizio

The last Number Placement playoff puzzle from the World Puzzle Championship was a Skyscrapers (Gap) puzzle with an empty cell in each row and column. How long will it take you to solve David Altizio’s puzzle?

Skyscrapers (Gap) by David Altizio

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between number entry modes and a shading mode to mark the unused cells.)

Author/Opus: This is the 15th puzzle from guest contributor David Altizio.

Rules: Variation of Skyscrapers rules. Insert numbers into some cells of the grid so that each row and column of the grid contains the numbers from 1 to 5 once each and one gap. Each number in the grid represents the height of a building and the clues on the outside of the grid indicate how many buildings can be “seen” when looking from that direction. Taller buildings block the view of smaller buildings.

Estimated Difficulty: 1.5 stars

Solution: PDF for all Number Placement playoff puzzles.

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.

WSC Playoff Puzzle 9/10: Clone Shape Sudoku by Joseph Howard

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.

Clone Shape Sudoku by Joseph Howard

PDF

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

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.

WSC Playoff Puzzle 5/10: Clone Sudoku by Serkan Yürekli

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.

Clone Sudoku by Serkan Yürekli

PDF

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

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.

Multiples Sudoku by Thomas Snyder

[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.]

Multiples Sudoku by Thomas Snyder

PDF

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

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.

Birthday Bonus: Kurotto (Skyscrapers) by Prasanna Seshadri

Continuing another long-running tradition, we have a new Kurotto puzzle from Prasanna Seshadri marking his 32nd birthday.

Kurotto (Skyscrapers) by Prasanna Seshadri

(view directly for a larger image)

PDF

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

Theme: 32 on 3/2/23

Author/Opus: This is the 250th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Kurotto rules. Also, numbers outside the grid show the number of separate shaded cells visible in that direction. A segment of length N in a given direction is taken as a building of height N. Buildings of height N block the view of all buildings behind them of equal or lesser height.

See also this example:

Kurotto Skyscrapers by Serkan Yürekli

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 10:00, Master = 18:00, Expert = 36:00

Solution: To be added by next Sunday.

Note: Follow this link for classic Kurotto puzzles and this link for variations on Kurotto puzzles. If you are new to this puzzle type, here are our easiest Kurotto to get started on. More Kurotto puzzles can be found in the ebook Kurotto by Prasanna Seshadri.