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

Theme: 1 to 9

Author/Opus: This is the 230th puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Variation of Nurikabe rules. Every region of white cells must contain exactly two numbers (instead of one) and have total size equal to the sum of the two numbers.

Also, see this example:

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 3:15, Master = 6:15, Expert = 12:30

Solution: PDF and solving video.

Note: Follow this link for classic Nurikabe and this link for Nurikabe variations. If you are new to this puzzle type, here are our easiest Nurikabe puzzles to get started on. More Nurikabe puzzles can be in The Art of Puzzles, in our beginner-friendly book Logic Puzzles 101, and in the e-book Nurikabe by Ashish Kumar.

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

Theme: Why was 6 Afraid of 7?

Author/Opus: This is the 10th puzzle from guest contributor Sam Cappleman-Lynes.

Rules: Place the numbers in the indicated range (1-8) in some of the cells so that no number is repeated in any row or column. Numbers on the outside of the grid indicate the sums of adjacent number 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 = 12:00, Master = 20:00, Expert = 40:00

Solution: PDF and solving video.

Note: Follow this link for other Japanese Sums puzzles.

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

Theme: Twenty20 Vision

Author/Opus: This is the 238th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Place the numbers in the indicated range (1-9) in some of the cells so that no number is repeated in any row or column. Numbers on the outside of the grid indicate the sums of adjacent number groups in that row or column, in order. Each sum is separated by at least one unused cell. The adjacent question marks (??) show two-digit numbers, not two groups)

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 6:00, Master = 9:15, Expert = 18:30

Solution: PDF and solving video.

Note: Follow this link for other Japanese Sums puzzles.

(view directly for a larger image)

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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: Diamonds

Author/Opus: This is the 237th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Balance Loop rules. Also, number clues are not fully specified and must strictly follow the inequality values given.

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 9:00, Master = 16:00, Expert = 32:00

Solution: PDF and solving video.

Note: Follow this link for other Balance Loop puzzles. If you are new to this puzzle type, here are our easiest Balance Loop Puzzles to get started on. More Balance Loops can be found in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli and in Balance Loop by Prasanna Seshadri and Murat Can Tonta.

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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: Antisymmetry

Author/Opus: This is the 7th puzzle from guest contributor wormsofcan.

Rules: (Standard Balance Loop rules.) Draw a single, non-intersecting loop that passes through all circled cells. All white circles must have equal segment lengths on both sides of the circle before turning. All black circles must have unequal segment lengths on both sides of the circle before turning. Numbers indicate the sum of the segment lengths on both sides of the circle.

Also, see this example:

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 4:45, Expert = 9:30

Solution: PDF and solving video.

Note: Follow this link for other Balance Loop puzzles. If you are new to this puzzle type, here are our easiest Balance Loop Puzzles to get started on. More Balance Loops can be found in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli and in Balance Loop by Prasanna Seshadri and Murat Can Tonta.

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

Theme: Channels

Author/Opus: This is the 95th puzzle from our contributing puzzlemaster Ashish Kumar.

Rules: Standard Sudoku rules.

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 8:30, Master = 13:00, Expert = 26:00

Solution: PDF and solving video.

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.

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

Theme: Diagonal Bridge

Author/Opus: This is the 15th puzzle from guest contributor Swaroop Guggilam.

Rules: Standard Even/Odd Sudoku rules (i.e., cells with a square contain an even digit; cells with a circle contain an odd digit).

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 5:45, Master = 9:30, Expert = 19:00

Solution: PDF and solving video.

Note: Follow this link for more Even/Odd Sudoku puzzles. If you are new to this puzzle type, here are our easiest Even/Odd Sudoku to get started on. More Even/Odd Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 1.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a composite mode for line/edge drawing and a number entry mode.)

Theme: Series

Author/Opus: This is the 30th puzzle from guest contributor Joseph Howard.

Rules: (Hybrid of Fillomino and Snake Puzzles.) Divide the grid along the boundary lines so that every cell belongs to a snake. A snake is a one-cell-wide path at least two cells long that does not touch itself, not even diagonally. Circled cells must be at one of the ends of a snake. A snake may contain one circled cell, two circled cells, or no circled cells at all. Numbered cells must be part of a snake with a length of exactly that number of cells. A snake may contain one number, multiple identical numbers, or no numbers at all. Two snakes of the same length cannot touch each other horizontally or vertically. Cells with an X cannot be an end of a snake.

Also see this example:

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 9:00, Master = 16:00, Expert = 32:00

Solution: PDF and solving video.

Note: Follow this link for more Snake Pit puzzles. Follow these links for other Fillomino or Snake puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a composite mode for line/edge drawing and a number entry mode.)

Theme: Surrounded

Author/Opus: This is the 236th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: (Hybrid of Fillomino and Snake Puzzles.) Divide the grid along the boundary lines so that every cell belongs to a snake. A snake is a one-cell-wide path at least two cells long that does not touch itself, not even diagonally. Circled cells must be at one of the ends of a snake. A snake may contain one circled cell, two circled cells, or no circled cells at all. Numbered cells must be part of a snake with a length of exactly that number of cells. A snake may contain one number, multiple identical numbers, or no numbers at all. Two snakes of the same length cannot touch each other horizontally or vertically. Cells with an X cannot be an end of a snake.

Also see this example:

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 6:00, Master = 8:30, Expert = 17:00

Solution: PDF and solving video.

Note: Follow this link for more Snake Pit puzzles. Follow these links for other Fillomino or Snake puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between ship placement and shading modes. In ship placement mode, right click gives sea, left click gives circle/square, left click and drag for rounded ships.)

Theme: The Right Ones

Author/Opus: This is the 17th puzzle from guest contributor Takeya Saikachi.

Rules: Standard Battleships rules. Use the indicated fleet.

Difficulty: 4 stars

Time Standards (highlight to view): Grandmaster = 6:00, Master = 10:00, Expert = 20:00

Solution: PDF and solving video.

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