See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.

PDF

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

Author/Opus: This is the 399th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Yajilin rules.

Difficulty: 2 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.

See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.

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)

Author/Opus: This is the 398th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Castle Wall rules.

Difficulty: 2 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

Note: Follow this link for more Castle Wall puzzles. If you are new to this puzzle type, here are our easiest Castle Wall puzzles to get started on. More Castle Wall puzzles can be found in our beginner-friendly collection Intro to GMPuzzles as well as the larger collection Castle Wall, both by Serkan Yürekli.

PDF

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

Theme: Christmas Tree

Author/Opus: This is the 397th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Thermo-Sudoku rules.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 7:30, Master = 16:30, Expert = 33:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 2.

PDF

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

Theme: Spiral

Author/Opus: This is the 83rd puzzle from our contributing puzzlemaster Ashish Kumar.

Rules: Standard Sudoku rules.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:30, Master = 8:15, Expert = 16:30

Solution: PDF; a solution video is also available here.

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)

Theme: Diamonds

Author/Opus: This is the 4th puzzle from guest contributor R. Kumaresan.

Rules: Standard Sudoku rules.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 2:45, Master = 6:15, Expert = 12:30

Solution: PDF; a solution video is also available here.

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)

Theme: Gift Box

Author/Opus: This is the 9th puzzle from guest contributor Akash Doulani.

Rules: Standard Sudoku rules.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 2:15, Master = 5:15, Expert = 10:30

Solution: PDF; a solution video is also available here.

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 = big entries and Number candidate = small entries in the corners of cells.)

Theme: No BIG Deal

Author/Opus: This is the 13th puzzle from guest contributor Rajesh Kumar.

Rules: Standard Tight Fit Sudoku rules. Remember, the smaller number goes above the larger number in all slashed cells. The range of this puzzle is 1-9.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:15, Master = 2:30, Expert = 5:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for other Tight Fit Sudoku puzzles on this website. If you are new to this puzzle type, here are our easiest Tight Fit Sudoku to get started on. More Tight Fit Sudoku can be found in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli, in The Art of Sudoku 2, and in Masterpiece Sudoku Mix 5: Tight Fit Sudoku.

PDF

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

Theme: Step Pyramids

Author/Opus: This is the 347th puzzle from our managing editor Serkan Yürekli.

Rules: Standard Isodoku rules, using numbers 1-8.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:15, Master = 2:15, Expert = 4:30

Solution: PDF; a solution video is also available here.

Note: Follow this link for other Isodoku. If you are new to this puzzle type, here are our easiest Isodoku to get started on.

PDF

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

Theme: Second Generation

Author/Opus: This is the 56th puzzle from our contributing puzzlemaster Palmer Mebane.

Rules: Standard Statue Park rules. This puzzle uses a standard pentomino set.

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 6:00, Master = 10:30, Expert = 21:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for other classic Statue Park and this link for Statue Park variations. If you are new to this puzzle type, here are our easiest Statue Parks to get started on. More Statue Park puzzles can be found in the ebook Statue Park by Murat Can Tonta.

PDF

or solve online (using our beta test of Penpa-Edit tools; use the tab key to alternate between shading and number entry modes)

Theme: Six Afraid of Seven

Author/Opus: This is the 55th puzzle from our contributing puzzlemaster Palmer Mebane.

Rules: Standard Nanro rules.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 3:45, Master = 7:30, Expert = 15:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for Nanro puzzles on this website and this link for variations on Nanro puzzles. If you are new to this puzzle type, here are our easiest Nanro Puzzles to get started on. More Nanro puzzles can be found in A Number o’ Nanro by Prasanna Seshadri.