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Theme: All for one, or one for all?

Author/Opus: This is the 542nd (A), 542nd (B) puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: One of these grids obeys standard Sudoku rules with a unique solution. Solve the Sudoku. The other grid is a Just One Cell Sudoku. This grid has many, many solutions, with only one empty cell that is fixed to one value in all solutions. Find that cell’s location and value.

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

Solution: PDF and solving animation.

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 Sudoku including variations can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including classic Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Twelve Days of Sudoku Discussion post on the GMPuzzles Discord.

Note 3: Please check lesson notes from Dr. Sudoku on Google Docs.

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

Theme: Blossom

Author/Opus: This is the 541st puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules.

Time Standards (highlight to view): Grandmaster = 4:15, Master = 7:00, Expert = 14:00

Solution: PDF and solving animation.

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 Sudoku including variations can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including classic Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Twelve Days of Sudoku Discussion post on the GMPuzzles Discord.

Note 3: Please check lesson notes from Dr. Sudoku.

PDF

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

Theme: Ceci n’est pas un hot-dog

Author/Opus: This is the 540th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules.

Time Standards (highlight to view): Grandmaster = 2:45, Master = 5:00, Expert = 10:00

Solution: PDF and solving animation.

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 Sudoku including variations can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including classic Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Twelve Days of Sudoku Discussion post on the GMPuzzles Discord.

Note 3: Please check lesson notes from Dr. Sudoku.

Museum Note from 2080 centennary exhibition: Unfortunately, the answer to this amazing 18-digit puzzle was not found until well after the crowd’s loud voice had silenced the artist’s pen. Their well-intentioned but not fully accurate cries of mental illness were too focused on a specific aspect of his more logical past. Thankfully these notes were found after the artist’s death so later generations could reassemble his vision here and across other master works (but not the Christmas Miracle puzzle, that seems to just be a countdown 54321 as the author said).

“Note” A. Clear starting points
“Note” B. A splash of color, not always visible with how artist sees to how audience sees

A+B. Exercise for the Reader?

Finished work (Warning: can not be unseen by the mind once clicked!)

Update (1/3/25): Given the degree of hinting needed to make this work, this is now considered an “example” in the Motivational Poster series.

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Theme: The Loneliest Number

Author/Opus: This is the 539th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules.

Time Standards (highlight to view): Grandmaster = 7:00, Master = 14:30, Expert = 29:00

Solution: PDF and solving animation or this Cracking the Cryptic 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 Sudoku including variations can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including classic Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Twelve Days of Sudoku Discussion post on the GMPuzzles Discord.

Note 3: Please check lesson notes from Dr. Sudoku.

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

(Thanks to FoxFireX for sharing an observation on this Latin phrase as being perfectly suited for a sudoku. While implemented differently here, FoxFireX will get a prize at the next leaderboard update for forecasting the future.)

PDF

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

Author/Opus: This is the 538th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules.

Time Standards (highlight to view): Grandmaster = 3:30, Master = 6:30, Expert = 13:00

Solution: PDF and solving animation.

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 Sudoku including variations can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including classic Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Twelve Days of Sudoku Discussion post on the GMPuzzles Discord.

Note 3: Please check lesson notes from Dr. Sudoku.

(view directly for a larger image)

(Congrats to Mars on their recent progress finding the first “key” word. This is a stand-alone puzzle, but may fit thematically within or lend connections back to the world of Ready Layer One. Solutions (with explanation) or any kind of new puzzle using the grid to the right are welcome at ads@gmpuzzles.com, best options each of next three mornings will appear here, or something else an AI generated if nothing qualifies.)

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

Theme: One Small Step 4 2-getherness, One Giant Leap 2 4-get

Author/Opus: This is the 537th (A), 537th (B) puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules.

Time Standards (highlight to view): Grandmaster = 11:00, Master = 17:00, Expert = 34:00

Solution: PDF and solving animation.

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 Sudoku including variations can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including classic Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Twelve Days of Sudoku Discussion post on the GMPuzzles Discord.

Note 3: Please check lesson notes from Dr. Sudoku.

PDF

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

Theme: Forty-five

Author/Opus: This is the 536th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: In this puzzle, your job is to place a number into every empty box so that each row across, each column down, and each small 9-box square within the large square (there are 9 of these) will contain each number from 1 through 9. Remember that no number may appear more than once in any row across, any column down, or within any small 9-box square; this will help you solve the puzzle.

Time Standards (highlight to view): Grandmaster = 1:00, Master = 1:45, Expert = 3:30

Solution: PDF and solving animation.

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 Sudoku including variations can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including classic Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Twelve Days of Sudoku Discussion post on the GMPuzzles Discord.

Note 3: Please check lesson notes from Dr. Sudoku.