Here are our best Number Placement puzzles of 2021 selected from the 58 web posts in this category based on FAVE votes, web comments, and tester comments. All of these puzzles are gathered in this PDF file.

Some of the best puzzles start with a simple premise, and Grant Fikes’ TomTom (Twins) that duplicates clue values — but doesn’t share those values except for the cage signs — was an enjoyable puzzle concept from last year and one of our Best of 2021 puzzles.

Another idea of duplication, this time within clue entries, led to this challenging Kakuro (Duplicate) by Thomas Snyder, “Nothing Unusual to See Here”.

2021 brought a new contributing puzzlemaster to the site in JinHoo Ahn, who constructed several of the best puzzles of the year. In this category, two of his Skyscrapers puzzles got a lot of attention. First was this easier (but unusual) Skyscrapers called “Triplets”.

Getting even more votes and tying for our best number placement puzzle of 2021 was this Skyscrapers (Cipher) puzzle also by JinHoo Ahn with a compass direction theme in the letter clues and an interesting logical path to follow as well.

Sharing the top billing for Best Number Placement puzzle of 2021 is this Japanese Sums by Prasanna Seshadri. While not yet a regular style for the site, we are seriously considering adding in this genre to the site after seeing a few creative Japanese Sums puzzles during this year including this “Stopped on the Way Back” theme with increasing number series clues.

We’ll start our Best of 2021 posts with some stats for the year.

2021 was a “full” year for us with over 320 web puzzles on the site, as well as twelve book releases including our first volumes of Grandmaster Puzzles Quarterly and the Masterpiece Sudoku Mix series. All told we released over 40 hours of web content and over 80 hours of book content (based off median solve times). In past years, when I’ve been changing jobs and/or moving cities, we would have to pause the site for a bit. Now with Serkan Yürekli as managing editor we have gotten to a regular publication schedule even when my science work has been chaotic (and this past year of COVID research and trying to balance time in SF and Seattle was chaotic). So kudos to Serkan and the other parts of the GMPuzzles team for keeping us on track. I’ll have more thoughts on our progress through the year in our OKR posts in the next week.

In reviewing our favorite puzzles of the year, we will start with Sudoku which was featured in 55 webposts this year. As in years past, we selected the top Sudoku by reviewing FAVE votes, web comments, and tested comments. All of these puzzles are gathered in this PDF file.

We introduced “Sunday Stumpers” as a new concept this year and our first Best of winner was a challenging Killer Sudoku by Prasanna Seshadri, “Y Go Extra?”

A few classic Sudoku stood out during the year. While primarily needing basic steps, the narrow solving path and challenging deductions of this “Two Snakes” Sudoku by Ashish Kumar got many favorite votes.

Another variation, Killer Su-Do-Ku by Michael Rios, got even more votes of approval despite its very difficult challenge.

Our two favorite sudoku of the year both came from Thomas Snyder / Dr. Sudoku, including this “Gridlocked” Sudoku that has a really interesting collision of logical steps to tease apart the answer.

The top sudoku of 2021, as well as one of the Top 3 overall puzzles for 2021, was this “Christmas Tree”-themed Thermo-Sudoku that was part of our last official week of 2021. The visual and logical theme elements worked together in this creative construction that got a lot of FAVE votes in a very short time.

Happy New Year to our GMPuzzles fans!

For those that missed it, we just released Grandmaster Puzzles Quarterly: Volume 2, a collection of ninety-six puzzles across six genres: Isodoku, Kakuro, Statue Park, LITS, Cave, and Slitherlink.

This next week will again be “off” from regular puzzle posts. But we still plan to post some different kinds of content and updates. We intend to share our Best of 2021 puzzles, make some updates to Penpa-Edit, grade our 2021 Objectives and Key Results (OKRs) and share our 2022 OKRs and book plans.

Coming in just before the end of 2021, we’re releasing our second quarterly mix of puzzles. Grandmaster Puzzles Quarterly: Volume 2 comes in at over 150% the size of the first volume, with a total of ninety-six puzzles across six genres:

– 12 Isodoku and 4 Isodoku (Consecutive Pairs)
– 12 Kakuro and 4 Kakuro (Hex)
– 12 Statue Park and 4 Statue Park (Half and Half)
– 12 LITS and 4 Easy as LITS
– 12 Cave and 4 Cave (Product)
– 12 Slitherlink and 4 Slitherlink (Sheep and Wolves)

As you’d expect from us, this collection includes a set of really elegant puzzles from twenty-one of the world’s best authors. We’re already working on volumes 3 and 4 (planned for publication in March and June of 2022) and will have more info on 2022 book plans and possible subscription options in the coming weeks for all of our 2022+ books. For now, we wish you a Happy New Year and hope you consider purchasing this excellent collection of logic puzzles as a way to start 2022 off in a great way.

See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.

PDF

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

Author/Opus: This is the 407th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Skyscrapers rules; also standard TomTom rules. Use the integers 1-7.

Difficulty: 3 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

Note: Follow this link for classic Skyscrapers puzzles and this link for variations on Skyscrapers puzzles. Follow this link for classic TomTom and this link for TomTom variations.

See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.

PDF

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

Author/Opus: This is the 406th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard TomTom rules, using the integers 1-7.

Difficulty: 4 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

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

See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.

PDF

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

Author/Opus: This is the 405th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Skyscrapers rules.

Difficulty: 3.5 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

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

See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.

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.)

Author/Opus: This is the 404th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Variation of Battleships rules; only two ship segments can belong in each marked region.

Difficulty: 2.5 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

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.

See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.

PDF

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

Author/Opus: This is the 403rd puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Star Battle rules. Two stars per row, column, and region.

Difficulty: 4 stars (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

Note: Follow this link for other classic Star Battles and this link for Star Battle variations. If you are new to this puzzle type, here are our easiest Star Battles to get started on. More Star Battle puzzles can be found in The Art of Puzzles, in the books Star Battle by JinHoo Ahn and Star Battle 2 by JinHoo Ahn and Murat Can Tonta, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.

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.)

Author/Opus: This is the 402nd puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Battleships rules. Use the indicated fleet.

Difficulty: 1 star (estimate based off competition points; timing standards not available from our usual testers)

Solution: PDF

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.