Today’s second post is the first puzzle from Semi-Final B at the SudokuCon Just One Cell Competition. The other puzzles in Semi-Final B will be posted tomorrow.

PDF

or solve online in Penpa, or also solve online in SudokuPad as a new option (note: highly recommended to turn off “Mark Solved Digits” option if you use that in SudokuPad).

Author/Opus: This is the 575th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: This Sudoku does not have a unique solution for the full grid (it actually has a large number of solutions), but there is exactly one cell in which a number can be logically placed that is fixed across all solutions. Find this cell and its unique value.

This puzzle follows Classic Sudoku rules, so no number repeats in any row, column, or bold region.

Time Standards: This competition had 1-point (easy), 2-point (medium), 3-point (hard), or higher value puzzles. This would have been 2 points (medium category), roughly 1.5-2 minute target.

Solution: PDF

Note: Follow this link for other Just One Cell Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Just One Cell Sudoku Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.

Today includes two of the three Semi-Final A puzzles, starting with this one. The third puzzle in the semi-final will be posted tomorrow.

PDF

or solve online in Penpa, or also solve online in SudokuPad as a new option (note: highly recommended to turn off “Mark Solved Digits” option if you use that in SudokuPad).

Author/Opus: This is the 574th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: This Sudoku does not have a unique solution for the full grid (it actually has a large number of solutions), but there is exactly one cell in which a number can be logically placed that is fixed across all solutions. Find this cell and its unique value.

This puzzle follows Classic Sudoku rules, so no number repeats in any row, column, or bold region.

Time Standards: This competition had 1-point (easy), 2-point (medium), 3-point (hard), or higher value puzzles. This would have been 2 points (medium category), roughly 1.5-2 minute target.

Solution: PDF

Note: Follow this link for other Just One Cell Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Just One Cell Sudoku Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.

The 24 main puzzles for the Just One Cell Competition at SudokuCon that have been featured over the last two weeks are here:

Qualifier Test PDF

Qualifier Solutions PDF

After 36 minutes, there was one perfect finisher and several other high scores on that qualifier that moved onto the playoffs where two groups of four matched up to determine a final four and then just one winner. Starting tomorrow we will feature the semifinal puzzles, while today we have some extras kept as back-ups.

While our Just One Cell posts end on June 6th, we have some exciting things coming June 7th, so keep coming back to see what is next for the future of Sudoku on GMPuzzles.

This is the first of two qualifier puzzles posting today in this style (following an easy warm-up); both are roughly the same difficulty with harder Killers coming tomorrow.

PDF

or solve online in Penpa, or also solve online in SudokuPad as a new option (note: highly recommended to turn off “Mark Solved Digits” option if you use that in SudokuPad).

Author/Opus: This is the 573rd puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: This Sudoku does not have a unique solution for the full grid (it actually has a large number of solutions), but there is exactly one cell in which a number can be logically placed that is fixed across all solutions. Find this cell and its unique value.

This puzzle follows Killer Sudoku rules, so no number repeats in any row, column, or bold region. The sum of the numbers in each cage must equal the value given in the upper-left corner of that cage. Numbers cannot repeat inside a cage.

Time Standards: This competition had 1-point (easy), 2-point (medium), 3-point (hard), or higher value puzzles. This was worth 1 point (easy category), roughly .75-1 minute target.

Solution: PDF

Note: Follow this link for other Just One Cell Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Just One Cell Sudoku Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.

This is the second of two puzzles posting today in this style, both of similar difficulty.

PDF

or solve online in Penpa, or also solve online in SudokuPad as a new option (note: highly recommended to turn off “Mark Solved Digits” option if you use that in SudokuPad).

Author/Opus: This is the 572nd puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: This Sudoku does not have a unique solution for the full grid (it actually has a large number of solutions), but there is exactly one cell in which a number can be logically placed that is fixed across all solutions. Find this cell and its unique value.

This puzzle follows Thermo-Sudoku rules, so no number repeats in any row, column, or bold region. Some thermometer shapes are in the grid; numbers must be strictly increasing from the round bulb to the flat end.

Time Standards: This competition had 1-point (easy), 2-point (medium), 3-point (hard), or higher value puzzles. This was worth 2 points (medium category), roughly 1.5-2 minute target.

Solution: PDF

Note: Follow this link for other Just One Cell Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Just One Cell Sudoku Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.

This is the first of two puzzles posting today in this style, both of similar difficulty.

PDF

or solve online in Penpa, or also solve online in SudokuPad as a new option (note: highly recommended to turn off “Mark Solved Digits” option if you use that in SudokuPad).

Author/Opus: This is the 571st puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: This Sudoku does not have a unique solution for the full grid (it actually has a large number of solutions), but there is exactly one cell in which a number can be logically placed that is fixed across all solutions. Find this cell and its unique value.

This puzzle follows Thermo-Sudoku rules, so no number repeats in any row, column, or bold region. Some thermometer shapes are in the grid; numbers must be strictly increasing from the round bulb to the flat end.

Time Standards: This competition had 1-point (easy), 2-point (medium), 3-point (hard), or higher value puzzles. This was worth 2 points (medium category), roughly 1.5-2 minute target.

Solution: PDF

Note: Follow this link for other Just One Cell Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Just One Cell Sudoku Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.

This is the second of two puzzles posting today in this style, and is likely the harder of the pair.

PDF

or solve online in Penpa, or also solve online in SudokuPad as a new option (note: highly recommended to turn off “Mark Solved Digits” option if you use that in SudokuPad).

Author/Opus: This is the 570th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: This Sudoku does not have a unique solution for the full grid (it actually has a large number of solutions), but there is exactly one cell in which a number can be logically placed that is fixed across all solutions. Find this cell and its unique value.

This puzzle follows Even/Odd Sudoku rules, so no number repeats in any row, column, or bold region. Cells with a square must contain an even number; cells with a circle must contain an odd number.

Time Standards: This competition had 1-point (easy), 2-point (medium), 3-point (hard), or higher value puzzles. This was worth 3 points (hard category), roughly 2.5-3 minute target.

Solution: PDF

Note: Follow this link for other Just One Cell Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Just One Cell Sudoku Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.

At SudokuCon, I brought together a lot of my stories and talks from 2006-2011 to tell my story of “How to Solve Sudoku Like a World Champion”. This video should tell you a lot about me and my journey to winning three world championships as well as some of unexpected things that go alongside that. The video should also (A) give you insights into ways to scan and notate Sudoku and when to apply them, (B) show you how to train for competitions and know you are making progress, and (C) offer up some other interesting ideas on geometry, sudoku construction, and more. On YouTube, there are many chapter marks to help explore the video for specific topics.

This is the first of two puzzles posting today in this style.

PDF

or solve online in Penpa, or also solve online in SudokuPad as a new option (note: highly recommended to turn off “Mark Solved Digits” option if you use that in SudokuPad).

Author/Opus: This is the 569th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: This Sudoku does not have a unique solution for the full grid (it actually has a large number of solutions), but there is exactly one cell in which a number can be logically placed that is fixed across all solutions. Find this cell and its unique value.

This puzzle follows Classic Sudoku rules, so no number repeats in any row, column, or bold region.

Time Standards (highlight to view): This competition had 1-point (easy), 2-point (medium), 3-point (hard), or higher value puzzles. This was worth 3 points (hard category), roughly 2.5-3 minute target.

Solution: PDF

Note: Follow this link for other Just One Cell Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Just One Cell Sudoku Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.

This is the second of two puzzles posting today in this style.

PDF

or solve online in Penpa, or also solve online in SudokuPad as a new option (note: highly recommended to turn off “Mark Solved Digits” option if you use that in SudokuPad).

Author/Opus: This is the 568th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: This Sudoku does not have a unique solution for the full grid (it actually has a large number of solutions), but there is exactly one cell in which a number can be logically placed that is fixed across all solutions. Find this cell and its unique value.

This puzzle follows Classic Sudoku rules, so no number repeats in any row, column, or bold region.

Time Standards (highlight to view): This competition had 1-point (easy), 2-point (medium), 3-point (hard), or higher value puzzles. This was worth 3 points (hard category), roughly 2.5-3 minute target.

Solution: PDF

Note: Follow this link for other Just One Cell Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Just One Cell Sudoku Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.