[This is a repost from our archives with new notes at the top (original post here): This challenging sudoku combines both the deficit and surplus varieties and will force you to think about what numbers are absent or repeated in the seven-/nine-cell regions. The combination of styles breaks down a lot of the standard Sudoku rules and might make you ask “what is a Sudoku?” Are these puzzles in that definition somewhere?]

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

Theme: L’s Big and Small

Rules: Combined Deficit and Surplus Sudoku rules, with some regions with fewer numbers (no repeats but one number missing) and others with more numbers (1-8 plus one repeat) than expected in a Sudoku. Use numbers from 1-8.

Estimated Difficulty*: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:30, Master = 7:00, Expert = 14:00

Solution: PDF

[This is a repost from our archives with new notes at the top (original post here): This puzzle was perhaps easier than the Wednesday Slitherlink; by time standards it is about the same, but this grid is larger. However that was partially by design as this TIME puzzle would be on a weekend many readers of that magazine might click over to the site due to a world puzzle championship article. This is a puzzle that isn’t too hard if you try to intuit how the loop goes, but it is not using as many common patterns to get started.]

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or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: Just in TIME? A hard Slitherlink puzzle from US Puzzle Team member Thomas Snyder, one of the “Answer Men” profiled in this week’s issue (subscription required).

Rules: Standard Slitherlink rules.

Estimated Difficulty*: 3 stars

Time Standards (highlight to view): Grandmaster = 3:15, Master = 4:00, Expert = 8:00

Note: Advice on solving this puzzle has now been posted in “Ask Dr. Sudoku #9”

Solution: PDF

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

[This is a repost from our archives with new notes at the top (original post here): Where Deficit Sudoku (Udoku) focuses on “naked single” type information with the altered rules, my own counterpart variation of Surplus Sudoku (Ssudoku) focuses on “hidden single” type information as all large regions must have one of each number (and one duplicate). This mid-week puzzle was trying to be on the easier end to be a parallel entry point into Surplus Sudoku that the Tuesday puzzle was for Deficit Sudoku.]

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Theme: Double Diagonals

Rules: Standard Surplus Sudoku rules, with numbers from 1-8.

Estimated Difficulty*: 2.5 stars

Time Standards (highlight to view): Grandmaster = 1:45, Master = 2:45, Expert = 5:30

Solution: PDF

[This is a repost from our archives with new notes at the top (original post here): The center field of 1’s is a quite unusual slitherlink pattern that became the focus for the whole solve here and a somewhat challenging puzzle. Another property that makes the grid hard is the absence of any 0’s that usually drive a faster solve. I often find myself making Slitherlinks without zeroes as a way to help my puzzles stand out a bit more.]

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: All for One and One for All

Rules: Standard Slitherlink rules.

Estimated Difficulty*: 3 stars

Time Standards (highlight to view): Grandmaster = 2:15, Master = 4:00, Expert = 8:00

Solution: PDF

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

[This is a repost from our archives with new notes at the top (original post here): My first experience with Deficit Sudoku, originally from Wei-Hwa Huang and named “Udoku”, was at the second World Sudoku Championship in Prague. By the time we wrote the style into our Mutant Sudoku book, we had renamed the variation to Deficit Sudoku. This theme recalls a special challenge Wei-Hwa made in that first set using the digits 0-9; in this case, I could make a similar think outside the box theme with just 1-7, keeping the 7 as an unseen number.]

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

Theme: Not Your Standard 6×6 Sudoku! An homage to my favorite (10×10) puzzle from the original “Udoku” set of Deficit Sudoku by Wei-Hwa Huang.

Rules: Standard Deficit Sudoku rules, with numbers from 1-7.

Estimated Difficulty*: 2 stars

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

Solution: PDF

[This is a repost from our archives with new notes at the top (original post here): Slitherlink has a simple rule set but an amazing amount of patterns and other deductions that flow out from it. Across this week I wanted to make some puzzles that were both visually elegant but also slowly went from common patterns to less common or rarely seen patterns.]

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or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: Parquet

Rules: Standard Slitherlink rules.

Estimated Difficulty*: 1.5 stars

Time Standards (highlight to view): Grandmaster = 0:40, Master = 1:15, Expert = 2:30

Solution: PDF

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

Our eighth Smashing the Sudoku video for “Fleet Week” is now live:

We have two more weeks in this look back series and then we will be putting our attention to a new subscription model for daily puzzles starting in April. While we have a long-term goal of having a full digital platform to deliver puzzles, we will get started by using Discord to support a Penpa + PDF delivery of two puzzles per day. Discord should also allow for a more dynamic conversation ability between our constructors and our audience while we gather feedback on features for the future.

Look to this Sunday update space for more details on our Discord invites and on how to get an early subscription before our April launch.

[This is a repost from our archives with new notes at the top (original post here): This rough Battleship Sudoku is a bit of a mind twister, at least until you carefully consider both how the fleet gets placed and what is special about the values across the boats. It is a quintessential example of the Battleship Sudoku that were in my first (and long since out-of-print) book that I might republish someday.]

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or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between number placement, ship placement, and shading modes. The shading mode in gray, which numbers can be written on top of, may work better than default ship placement.)

Theme: Twister

Rules: Standard Battleship Sudoku rules.

Estimated Difficulty*: 4 stars

Time Standards (highlight to view): Grandmaster = 5:45, Master = 10:30, Expert = 21:00

Solution: PDF

[This is a repost from our archives with new notes at the top (original post here): This final “classic” Battleships puzzle in fleet week highlights another unusual grid with lots of small clue values limiting the columns. Some crafty logic will get you through to the finish.]

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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 Bermuda Quadrangle? The missing radar clues will complicate the solve.

Rules: Standard Battleships rules.

Estimated Difficulty*: 3 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 6:30, Expert = 13:00

Solution: PDF; advice on solving this puzzle was also posted in “Ask Dr. Sudoku #8“.

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.

[This is a repost from our archives with new notes at the top (original post here): This unusual Battleship Sudoku starts with all four of its submarines given. It is left as an exercise for the solver to figure out if that makes placing the other ships (with their labeled numbers) any easier.]

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between number placement, ship placement, and shading modes. The shading mode in gray, which numbers can be written on top of, may work better than default ship placement.)

Theme: Four Islands

Rules: Standard Battleship Sudoku rules.

Estimated Difficulty*: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:45, Master = 9:00, Expert = 18:00

Solution: PDF

Note: Advice on solving this puzzle was posted in “Ask Dr. Sudoku #8“