### Arrow/Killer/Kropki/Thermo-Sudoku by Michael Rios

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Theme: Square Knots

Author/Opus: This is the 2nd puzzle from guest contributor Michael Rios.

Rules: Standard Sudoku rules. Also, some arrow shapes are in the grid; the sum of the digits along the path of each arrow must equal the digit in the circled cell (digits can repeat on an arrow). Some cages are in the grid marked by dashed lines; the sum of the digits in these cages must equal the value given in the upper-left corner of that cage (digits cannot repeat inside a cage). Some dots are given between two cells; a white dot shows that the digits in those cells are consecutive and a black dot shows that the digit in one of the cells has twice the value of the other (adjacent cells without dots may or may not follow these rules). Finally, some thermometer shapes are in the grid; the digits along the thermometer must be strictly increasing from the round bulb to the flat end.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 10:45, Master = 18:45, Expert = 37:30

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

Note: Follow this link for more Arrow Sudoku. Follow this link for more Thermo-Sudoku puzzles. More Arrow and Thermo-Sudoku puzzles can be found in The Art of Sudoku 2. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.

### Arrow/Thermo-Sudoku by JinHoo Ahn

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Theme: Antisymmetry

Author/Opus: This is the 30th puzzle from our contributing puzzlemaster JinHoo Ahn.

Rules: Standard Arrow Sudoku rules. Also, standard Thermo-Sudoku rules.

Difficulty: 2.5 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 3:15, Expert = 6:30

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

Note: Follow this link for more Arrow Sudoku. Follow this link for more Thermo-Sudoku puzzles. More Arrow and Thermo-Sudoku puzzles can be found in The Art of Sudoku 2.

### Arrow Sudoku (Cipher) by Ashish Kumar

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Theme: Poker Face

Author/Opus: This is the 75th puzzle from our contributing puzzlemaster Ashish Kumar.

Rules: Standard Arrow Sudoku rules. Also, some of the digits in the circles are encrypted with letters. Each letter represents a different positive integer, for the solver to determine.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 7:00, Master = 17:30, Expert = 35:00

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

Note: Follow this link for more Arrow Sudoku. If you are new to this puzzle type, here are our easiest Arrow Sudoku to get started on. More Arrow Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 3.

### Arrow Sudoku (Product) by JinHoo Ahn

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Theme: Double X

Author/Opus: This is the 14th puzzle from our new contributing puzzlemaster JinHoo Ahn.

Rules: Variation of Arrow Sudoku rules. Instead of the usual meaning, the digit in the circled cell of each arrow must equal the product of the digits along the path.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 3:30, Master = 4:45, Expert = 9:30

Solution: PDF; a solution video (with info on an Easter Egg for this puzzle) is also available here.

Note: Follow this link for more Arrow Sudoku. If you are new to this puzzle type, here are our easiest Arrow Sudoku to get started on. More Arrow Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 3.

### Arrow Sudoku by Swaroop Guggilam

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Theme: House

Author/Opus: This is the 10th puzzle from guest contributor Swaroop Guggilam.

Rules: Standard Arrow Sudoku rules.

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 7:30, Master = 13:00, Expert = 26:00

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

Note: Follow this link for more Arrow Sudoku. If you are new to this puzzle type, here are our easiest Arrow Sudoku to get started on. More Arrow Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 3.

### Arrow Sudoku by Akash Doulani

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Theme: Vacant Room

Author/Opus: This is the 5th puzzle from guest contributor Akash Doulani.

Rules: Standard Arrow Sudoku rules.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 5:30, Master = 7:30, Expert = 15:00

Solution: PDF

Note: Follow this link for more Arrow Sudoku. If you are new to this puzzle type, here are our easiest Arrow Sudoku to get started on. More Arrow Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 3.

### Arrow Sudoku by Rajesh Kumar

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Theme: Standing Man

Author/Opus: This is the 8th puzzle from guest contributor Rajesh Kumar.

Rules: Standard Arrow Sudoku rules.

Difficulty: 2.5 stars

Time Standards (highlight to view): Grandmaster = 3:00, Master = 4:00, Expert = 8:00

Solution: PDF

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

### Arrow Sudoku by Joseph Howard

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Theme: Fanned Out

Author/Opus: This is the 19th puzzle from guest contributor Joseph Howard.

Rules: Standard Arrow Sudoku rules.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:45, Master = 7:45, Expert = 15:30

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

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

### Best of 2019: Sudoku Puzzles

Here are our best Sudoku puzzles of 2019, selected from the 31 web posts in this category:

Our first favorite puzzle was a very nicely themed Killer Sudoku by Serkan Yürekli with a rocket theme and a visual countdown in the grid.

Guest contributor Chris Green put together a paired set of Tight Fit Sudoku with a really interesting challenge that stretched the way you tend to think about this style.

Our next two top Sudoku are both clueless varieties. First, from Thomas Snyder, aka Dr. Sudoku, is this clueless Arrow Sudoku.

Ashish Kumar made a clueless Thermo-Sudoku in preparation for the World Puzzle Championship that was also one of our top puzzles.

But the overall best sudoku of 2019 goes to an unusual puzzle which was a Birthday Surprise Sudoku from Prasanna Seshadri that was a nearly perfect puzzle for his 28th birthday.

All of these best Sudoku puzzles are collected in this PDF file.

### Arrow Sudoku by Thomas Snyder

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Theme: Clueless

Author/Opus: This is the 344th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Arrow Sudoku rules.

Answer String: Enter the 2nd row from left to right, followed by a comma, followed by the 8th row from left to right.

Time Standards (highlight to view): Grandmaster = 6:00, Master = 9:00, Expert = 18:00

Solution: PDF

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