Sunday Update

We’ve just published our fourth episode of Smashing the Sudoku as we look back at our first puzzles from ten years ago and try to bring back memories of these constructions from our first 60+1 puzzles:

In a few minutes we will also have our fourth Microsoft Puzzle Hunt bonus puzzle, which we hope you all enjoy.

Arrow Sudoku by Thomas Snyder

[This is a repost from our archives with new notes at the top (original post here): The third arrow Sudoku puzzle in our GMPuzzles introduction series contains a lot of “split” arrows with multiple paths all equaling the same total sum. Steady progress going arrow by arrow around the grid should let you eventually find the unique answer.]

Arrow Sudoku by Thomas Snyder

PDF

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

Theme: Multi-arrow Challenge! Also, there is a 1-9 “digit pangram” in the nine givens.

Rules: Standard Arrow Sudoku rules.

Estimated 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 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.

Cave by Thomas Snyder

[This is a repost from our archives with new notes at the top (original post here): The last Cave puzzle in our starting week has some interesting border clues that should set up for a different kind of solving path if you are paying attention.

Cave by Thomas Snyder

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

Theme: An Almost Perfect 10? The border of this Cave puzzle is almost completely uniform.

Rules: Standard Cave rules.

Estimated Difficulty*: 3 stars

Time Standards (highlight to view): Grandmaster = 3:15, Master = 6:00, Expert = 12:00

Solution: PDF and solving video.

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

Arrow Sudoku by Thomas Snyder

[This is a repost from our archives with new notes at the top (original post here): The best Arrow Sudoku puzzles usually have a few fully constrained arrow clues at the start to be the “seeds” for the logical path to the solution. Can you find where these seeds are in this “Flower Blossom” theme?

Arrow Sudoku by Thomas Snyder

PDF

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

Theme: Flower Blossom – The cells with arrows look a little like the petals of a flower and are heavily involved in the solving path.

Rules: Standard Arrow Sudoku rules.

Estimated Difficulty*: 2.5 stars

Time Standards (highlight to view): Grandmaster = 3:45, Master = 5:30, Expert = 11:00

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.

Mid-week update

After a tough January with assorted things like a power outage impacting our ability to compete on the United States Puzzle Championship, and many more events around my science work leading to a mental health break, we’re back on track for most of our 2023 projects. For Grandmaster Puzzles, we’ve now completed our recent “Best Of” series is now finished and we just released our third edition of “Smashing the Sudoku” to go along with our original 60+1 puzzle set.

Coming in the future will be some invites to puzzle contributors and top fans for our Discord channel where we are brainstorming what is next for the site (in 2023 and out to 2033 in a ten year plan), a new approach to web content, and more info on puzzle championships that GMPuzzles will be involved in.

Cave by Thomas Snyder

[This is a repost from our archives with new notes at the top (original post here): This puzzle highlights a lot of the standard Cave logical thinking (including a rule about checkerboards that we mentioned in a prior post needs to be in your toolbox for this genre). If you are struggling with this cave puzzle, an “Ask Dr. Sudoku” written piece may be worth referring to.

Cave by Thomas Snyder

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

Theme: “23” – Both the original posting date in 2013 (Jan 23), and a fine number for themed logic puzzles, such as the Map Puzzles from Bang 23.

Rules: Standard Cave rules.

Estimated Difficulty*: 2.5 stars

Time Standards (highlight to view): Grandmaster = 1:45, Master = 3:30, Expert = 7:00

Solution: PDF

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

Arrow Sudoku by Thomas Snyder

[This is a repost from our archives with new notes at the top (original post here): A good sudoku variant adds a small amount of new thinking on top of the basic Sudoku (three-way no repeat) rule; Arrow Sudoku fits that description perfectly with a few arithmetic deductions added on top of standard sudoku, and the potential for graphically interesting themes. This Arrow Sudoku puzzle should break apart easily once the “new” Arrow rule is properly considered.]

Arrow Sudoku by Thomas Snyder

PDF

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

Theme: Diagonals (two more than yesterday!)

Rules: Standard Arrow Sudoku rules. Range is 1-6.

Estimated Difficulty*: 1 star

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

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.

Best of 2022: Loop / Path

Our last category for the Best of 2022 posts is “Loop / Path” puzzles, where we had 59 posts during the year. All of the best puzzles are gathered in this PDF file.

Our first puzzle to earn best of ratings is a Slitherlink (Liar) puzzle by Thomas Snyder with a Bull’s-Eye theme. This puzzle hit the mark with its solvers by highlighting several different uses of the “lying” clues during the solve.

Slitherlink (Liar) by Thomas Snyder

or solve online (using our beta test of Penpa-Edit tools; use tab to switch between edgex mode where left click+drag draws lines and right click marks X’s, and a shading and number entry mode to mark/update the liar clues.)

Next up on the favorites list was an Equality puzzle by Murat Can Tonta, a loop variation featured in our Loop Variety Collection 2. This Equality puzzle has several different quadrants to work through and very interesting logic.

Equality by Murat Can Tonta

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between the default linex mode where left click+drag draws lines and right click marks X’s and a shading mode to help mark cells.)

Two Castle Wall puzzles earned top marks in 2022 but neither was “typical” in that they only used black clues. The first was a “Black Box” Castle Wall puzzle by JinHoo Ahn, another masterpiece from this talented puzzle designer.

Castle Wall by JinHoo Ahn

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)

Second best in category was another uncommon variation, this time an “unequal lengths” variation that we had seen in other loop styles but that shone through in this Slitherlink (Unequal Lengths) puzzle by Murat Can Tonta.

Slitherlink by Murat Can Tonta

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)

The best loop and best overall puzzle of 2022 was this Castle Wall gem that also uses just black clues in an interesting layout to reveal the one forced solution by an interesting logical path.

Castle Wall by Stefan Liew

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)

What did you think of these “best of 2022” puzzles? Add your comments to the posts and send your thanks to the authors for these great constructions.

Cave by Thomas Snyder

[This is a repost from our archives with new notes at the top (original post here): One of my favorite “underappreciated” puzzle styles is Cave, a genre that began as BAG from Nikoli (with rules consistent with other loop puzzle styles). The style passed through other names like Corral in the United States Puzzle Championship before being recast as a shading puzzle as Cave which is the GMPuzzles name. While the shading approach feels most natural to me, it does have one slight disadvantage from the loop version which is solvers need to learn an anti-checkerboard rule for themselves (i.e., you cannot have a 2×2 square which alternates between inside/outside cells as on a checkerboard). In the “loop” version of the rules, that grid state would require drawing four edges through a point and would violate the non-intersecting loop rule.

However you want to refer to this puzzle style, we hope that you enjoy this look back at some of the first Cave puzzles on the GMPuzzles site starting with this one featuring a long diagonal of clues.]

Cave by Thomas Snyder

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

Theme: Ascending/Descending Diagonal

Rules: Standard Cave rules.

Estimated Difficulty*: 1.5 stars

Time Standards (highlight to view): Grandmaster = 0:45, Master = 1:20, Expert = 2:40

Solution: PDF

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

Best of 2022: Region Division

Splitting apart a large grid into subregions or shapes is the unifying element for our “Region Division” category, where we will be announcing the five best of 2022 puzzles today selected from 47 posted puzzles. The “best of” puzzles are gathered together in this PDF file.

We kick off today’s “best of region division” section with this great Fillomino puzzle by Jonas Gleim. The separation of evens and odds leads to some interesting emergent logic as one works to the unique solution.

Fillomino by Jonas Gleim

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.)

Contributing puzzlemaster Takeya Saikachi drew a lot of attention with his puzzles in 2022 including this Cave (Myopia) combination that takes the familiar “Myopia” arrows and applies them to another genre where this was at least my first time seeing this kind of combination.

Cave (Myopia) by Takeya Saikachi

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

Early in each year we often post “New Year” puzzles with a clear 20XX theme. This 2022 Fillomino from Prasanna Seshadri was one of our first puzzles in the year and an instant “classic” destined for this best of ranking.

Fillomino by Prasanna Seshadri

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.)

While we can’t tell you the theme behind this Spiral Galaxies puzzle by Murat Can Tonta, one of the commenters said “This might be my favourite puzzle yet!” We think you might enjoy the solving path and hidden surprises too.

Spiral Galaxies by Murat Can Tonta

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 shading mode.)

While this was a very competitive category this year, the top puzzle stood out clearly from the rest and was another masterpiece by JinHoo Ahn who keeps finding impressive ways to use very few letters to make brilliant Pentominous puzzles. This elegant 8-letter Pentominous is our best Region Division puzzle of 2022.

Pentominous by JinHoo Ahn

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