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.

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

Author/Opus: This is the 405th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Skyscrapers rules.

Difficulty: 3.5 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

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.

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)

Author/Opus: This is the 403rd puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Star Battle rules. Two stars per row, column, and region.

Difficulty: 4 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

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.

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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.

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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: 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 tab to alternate between a composite mode for line/edge drawing, a letter entry mode, and shading / shape entry modes depending on how you want to mark the stars.)

Author/Opus: This is the 360th puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Combination of Pentominous and Star Battle. Place stars into some cells so that there are two stars in each row and column; no two stars can touch, even diagonally. Then divide the rest of the grid into 16 regions each containing 5 cells. Regions with the same shape (including rotations/reflections) cannot share an edge. A cell with a letter in it must be part of the pentomino shape normally associated with that letter; an inventory of pentominoes is given below the puzzle.

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 5:30, Master = 10:15, Expert = 20:30

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

Note: Follow this link for other Pentominous puzzles. If you are new to this puzzle type, here are our easiest Pentominous to get started on. More Pentominous puzzles can be found in the Plenty o’ Pentominous series by Grant Fikes and Murat Can Tonta 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 the tab key to alternate between shading, number entry, and composite loop drawing modes)

Theme: Clockwise

Author/Opus: This is the 21st puzzle from guest contributor Bryce Herdt.

Rules: Variation of Nanro rules. Label some cells with numbers to form a single non-intersecting loop; no 2×2 group of cells may be fully labeled, but the loop may touch itself orthogonally or diagonally. The region boundaries divide the loop into segments, and each region must have at least one segment. Numbers denote the length in cells of each segment within a region; all numbers in a region must be the same. When two numbers from different segments are orthogonally adjacent, the numbers must be different. (Consequently, segments in the same region must not share an edge.)

Also see this example:

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 5:00, Master = 12:30, Expert = 25:00

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.

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.

(This is a bonus “second” puzzle that is not connected to the usual Monday-Saturday week difficulty.)

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

Theme: Five Shurikens

Author/Opus: This is the 37th puzzle from our contributing puzzlemaster JinHoo Ahn.

Rules: Standard LITS rules.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 3:15, Master = 6:00, Expert = 12:00

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

Note: Follow this link for more variations of LITS and this link for classic LITS. If you are new to this puzzle type, here are our easiest LITS to get started on. More LITS puzzles can be found in LOTS O’ LITS by Grant Fikes and Prasanna Seshadri, in The Art of Puzzles 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: Five Shurikens

Author/Opus: This is the 36th puzzle from our contributing puzzlemaster JinHoo Ahn.

Rules: Shade some cells black so that in each region there are exactly four unshaded cells that form an L, I, T, S, or O tetromino. When two unshaded tetrominoes share an edge across regions, they must not be the same shape regardless of rotations or reflections. All shaded cells must be connected into a single group, but no 2×2 group of cells can be entirely shaded black.

Example by Thomas Snyder:

Difficulty: 5 stars

Time Standards (highlight to view): Grandmaster = 12:00, Master = 25:00, Expert = 50:00

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

Note: Follow this link for more variations of LITS and this link for classic LITS. If you are new to this puzzle type, here are our easiest LITS to get started on. More LITS puzzles can be found in LOTS O’ LITS by Grant Fikes and Prasanna Seshadri, in The Art of Puzzles 2, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.