PDF

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Theme: Diagonals

Author/Opus: This is the 226th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules. Additionally, there are two overlapping classic sudoku grids, and both must have valid solutions.

Note: No answer strings or timing here (honor system for when you solve it). I’m simply posting some “examples” I wrote as the Sudoku Grand Prix coordinator. Apparently some common variants aren’t common enough….

Solution: PDF

PDF

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Theme: Digit Series and Clue Symmetry

Author/Opus: This is the 225th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules. Additionally, some edges are marked with the sums of the digits in the adjacent cells.

Note: No answer strings or timing here (honor system for when you solve it). I’m simply posting some “examples” I wrote as the Sudoku Grand Prix coordinator. Apparently some common variants aren’t common enough….

Solution: PDF

PDF

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

Theme: Clue Symmetry and Logic

Author/Opus: This is the 77th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Sudoku rules. Also, around the three symbols (circle, diamond, and square), the indicated pairs of labelled cells must have identical sums.

Answer String: Enter the 4th 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 = 13:30, Expert = 27:00

Solution: PDF

Note: Follow this link for other less common 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: Sudoku GP Round 7 (this puzzle continues a hidden theme present throughout Prasanna’s Sudoku Grand Prix set)

Author/Opus: This is the 41st puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Sudoku rules. Additionally, all cells having the same digit(s) more than once as orthogonal neighbors are shaded. (If a cell is not shaded, it cannot have any digits repeated as orthogonal neighbors). Or see this example image.

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

Time Standards (highlight to view): Grandmaster = 9:00, Master = 17:30, Expert = 35:00

Solution: PDF; a solution video is available here.

Note: Follow this link for other less common 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: Sudoku GP Round 7, plus two hidden themes related to 7
(Note: this puzzle was originally created for the Sudoku Grand Prix but after testing was judged too hard and too puzzle-based for the competition. It is an excellent puzzle, and we are proud to showcase it here.)

Author/Opus: This is the 40th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Sudoku rules. Also, standard Skyscrapers rules. Additionally, the cells in gray are “underground” and cannot be seen by any of the outside skyscraper clues (think of them as starting with a negative sign if necessary). As an example, the 3 on the left of row 2 refers only to seeing three buildings in columns 2 through 9, even if there is a 9 in column 1 as that 9 cannot be seen.

Answer String: Enter the 1st row from left to right, followed by a comma, followed by the 5th row from left to right.

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

Solution: PDF

Note: Follow this link for our first Basement Skyscraper Sudoku. Follow this link for other less common 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

Author/Opus: This is the 54th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Variation of Sudoku rules. Every given clue is lying. The correct value is either one more or one less than the given clue. (1 clues cannot become 0, and 9 clues cannot become 10.)

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 = 5:30, Master = 8:00, Expert = 16:00

Solution: PDF

Note: Follow 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: Desperately Seeking Seven (Note: the shading of the “7” shaped region is just for artistic purposes.)

Author/Opus: This is the 173rd puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules (no repeats in any rows, columns, or bold regions). The digit range is 1-7.

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 = 1:15, Master = 2:00, Expert = 4:00

Solution: PDF

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.

PDF

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

Theme: Clue Symmetry and Logic

Author/Opus: This is the 17th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Variation of Sudoku rules. Each number in the top grid must be moved either up, down, left, or right the same number of cells as that number’s value without crossing the border of the grid. Numbers must all land on unique spots, but unlike in normal Hamle numbers may be adjacent after moving and white areas may not all be connected. Then solve the resulting sudoku. (Note: It is possible for a number to have two valid movement options in the solution; it is only required that at least one direction of movement exists for each number.)

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 = 9:30, Master = 15:00, Expert = 30:00

Solution: PDF

Note: Follow this link for other less common variations of Sudoku. Many specific variations of Sudoku have their own categories in the sidebar to the left. Follow this link for classic Sudoku.

PDF

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

Theme: Solve Me, I’m Irish

Author/Opus: This is the 94th puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Variation of Sudoku rules. Instead of the digits 1-9, use the letters in “SHIRT PACK”.

Answer String: Enter the 2nd row from left to right, followed by a comma, followed by the 8th row from left to right. Use capital letters (i.e. “SHIRTPACK”) when entering each row.

Time Standards (highlight to view): Grandmaster = 2:15, Master = 4:00, Expert = 8:00

Solution: PDF

Note: Follow this link for other less common variations of Sudoku. Many specific variations of Sudoku have their own categories in the sidebar to the left. Follow this link for classic Sudoku.

I’m sure many of you were expecting ANOTHER version of the Christmas Tree puzzle from the last two weeks. I mean, I did get a very nice Double Back from Robert Vollmert (which cannot be confused as a Star Battle or a LITS). But posting such a puzzle wouldn’t be a surprise.

No, today’s Sunday Surprise comes from the pile of submissions I’ve received over the year from Hans van Stippent, who played with the usual rules of Skyscrapers a bit by hiding some of the cells from consideration. It yielded a very interesting puzzle which is Hans’ gift to you this Sunday.

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Theme: New Variation/Logic

Rules: Standard Sudoku rules. Also, standard Skyscrapers rules. Additionally, the cells in gray are “underground” and cannot be seen for any of the outside skyscraper clues (think of them as starting with a negative sign if necessary). As an example, the 4 in row 2 refers only to seeing four buildings in columns 3 through 7, even if there is a 9 in column 1 or column 2 as that 9 cannot be seen.

Answer String: Enter the 1st row from left to right, followed by a comma, followed by the 9th row from left to right.

Solution: PDF