This year, we started posting some extra difficult Sunday Stumpers, about once a month. These will be quite tough puzzles, but with a logical path to be found (and solution videos to help). This tenth Sunday Stumper is a challenging Killer Sudoku by Prasanna Seshadri.

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

Theme: Y Go Extra?

Author/Opus: This is the 220th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Sudoku rules. Also, the sum of the digits in each cage must equal the value given in the upper-left corner of that cage. Digits cannot repeat inside a cage.

Difficulty: 5 stars

Time Standards (highlight to view): Grandmaster = 20:00, Master = 30:00, Expert = 1:00:00

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

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.

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

Theme: 23

Author/Opus: This is the 219th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Cross the Streams rules.

Difficulty: 2 stars

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

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

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

PDF

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

Theme: 4-way Intersections

Author/Opus: This is the 218th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Kakuro Rules.

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 6:30, Master = 9:30, Expert = 19:00

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

Note: Follow this link for classic Kakuro and this link for Kakuro variations. More Kakuro puzzles can be found in Kakuro and Variations by Serkan Yürekli and in The Art of Puzzles 2.

PDF

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

Theme: Antisymmetry

Author/Opus: This is the 217th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Statue Park rules. Also, the numbers in the black circles show the number of spaces not occupied by pentominoes in orthogonally and diagonally adjacent cells. The numbers in the white circles show the number of spaces occupied by pentominoes in orthogonally and diagonally adjacent cells.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 11:00, Master = 16:00, Expert = 32:00

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; in default linex mode: left-click+drag draws line, right click marks X on edge)

Theme: Number Series

Author/Opus: This is the 216th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Draw a single loop in the grid which may cross itself orthogonally, but otherwise does not touch or retrace itself. The clue numbers to the left/right of the rows indicate the number of squares visited by the nearest section of the loop that travels horizontally in the rows. The clue numbers to the top/bottom of the columns indicate the number of squares visited by the nearest section of the loop that travels vertically in the columns.

Also, see this example:

Difficulty: 1.5 stars

Time Standards (highlight to view): Grandmaster = 1:00, Master = 1:40, Expert = 3:20

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

Note: Follow this link for other Round Trip puzzles. Some more Round Trip puzzles can be found in the book Loop Variety Collection by Ashish Kumar and Murat Can Tonta.

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

Theme: It’s T Time

Author/Opus: This is the 215th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Sudoku rules. Also, the sum of the digits in each cage must equal the value given in the upper-left corner of that cage. Digits cannot repeat inside a cage.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 11:15, Master = 19:00, Expert = 38:00

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

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the composite Yajilin mode where left click marks cells, right click marks dots in cells or X’s on edges, left click+drag draws lines.)

Theme: Circle

Author/Opus: This is the 214th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Tapa rules.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 4:15, Expert = 8:30

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

Note: Follow this link for classic Tapa and this link for Tapa variations. If you are new to this puzzle type, here are our easiest Tapa puzzles to get started on. More Tapa puzzles can be found in The Art of Puzzles, in Tapa and Variations, and in our beginner-friendly collection Intro to GMPuzzles, all by Serkan Yürekli.

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)

Theme: One True King

Author/Opus: This is the 213th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Castle Wall rules.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:15, Master = 2:00, Expert = 4:00

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

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; use tab to alternate between shading and number placement modes.)

Theme: GMP! WOW WOW!

Author/Opus: This is the 212th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Tapa rules, except that the digits have been encoded with a cipher into letters. Each letter represents a different positive integer, for the solver to determine.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:45, Master = 3:15, Expert = 6:30

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

Note: Follow this link for classic Tapa and this link for Tapa variations. If you are new to this puzzle type, here are our easiest Tapa puzzles to get started on. More Tapa puzzles can be found in The Art of Puzzles, in Tapa and Variations, and in our beginner-friendly collection Intro to GMPuzzles, all by Serkan Yürekli.

PDF

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

Theme: Stopped on the Way Back

Author/Opus: This is the 211th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Place the digits 1-9 in some of the cells, so that no digit is repeated in any row or column. Numbers on the outside of the grid indicate the sums of adjacent digit groups in that row or column, in order. Each sum is separated by at least one unused cell. A ? can represent any sum of 1 or larger.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 10:00, Master = 19:15, Expert = 38:30

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

Note: Follow this link for other Japanese Sums puzzles.