[This is a repost from our archives with new notes at the top (original post here): This second isodoku on the site altered the standard cube shape significantly by flattening out the whole center by looking like a 3 by 3 by 3 cube was removed. The new region shapes now hold some important constraints to make progress in the puzzle.]

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Theme: Missing my Rubik’s? This isodoku has 27 fewer “cubes” than Monday’s puzzle.

Rules: Standard Isodoku rules, using numbers 1-8.

Estimated Difficulty*: 2.5 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 3:45, Expert = 7:30

Solution: PDF

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

[This is a repost from our archives with new notes at the top (original post here): Fillomino is one of our main “region division” puzzle styles, as you try to fit several polyominoes into a grid without similar size regions sharing an edge. In this first Fillomino puzzle on the site from ten years ago, the starting arrangement of 1-8 alongside other two by four groups sets up a beginner’s arrangement of numbers to fit into the grid.]

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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: Two by Fours

Rules: Standard Fillomino rules.

Estimated Difficulty*: 1.5 stars

Time Standards (highlight to view): Grandmaster = 1:15, Master = 1:30, Expert = 3:00

Solution: PDF

Note: Follow this link for other classic Fillomino and this link for more variations on Fillomino puzzles. If you are new to this puzzle type, here are our easiest Fillomino puzzles to get started on.

[This is a repost from our archives with new notes at the top (original post here): This last week of our “first 60” puzzles started with another interesting geometric sudoku variation, that almost looks three-dimensional and changes the meaning of “rows”. While future puzzles would use more altered isodoku shapes, the first puzzle needed to be a standard “cube” with two by four regions.]

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Theme: Peace!

Rules: Standard Isodoku rules, using numbers 1-8.

Estimated Difficulty*: 2 stars

Time Standards (highlight to view): Grandmaster = 1:30, Master = 3:00, Expert = 6:00

Solution: PDF

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

Our ninth Smashing the Sudoku video including Slitherlink and Deficit/Surplus Sudoku walkthroughs and an update on the Ten-Year Anniversary Contest is now posted:

This coming week will be the last in our look back series on our first 60+1 puzzles and we will then share more details on what is coming up in 2023 for GMPuzzles.

[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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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.]

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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: 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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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.