Sunday Special: Instructionless by Takeya Saikachi

Takeya Saikachi presents us with a new loop genre in which you need to discover the rules by solving the example first.

Instructionless by Takeya Saikachi

PDF

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

Theme: Triplets

Author/Opus: This is the 40th puzzle from our contributing puzzlemaster Takeya Saikachi.

Rules: To solve the main puzzle, you must first discover the genre’s rules by solving the example puzzle.

Example: solve online

Instructionless Example by Takeya Saikachi

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:35, Master = 7:15, Expert = 14:30

Hints: 1. This is a loop puzzle style that involves visiting all cells, forming a single closed loop. But what do the number clues do?
2. When thinking the right way, each number clue will have two uses.
3. Looking at individual clues may not be enough.
4. Pair all the clues together (as passed through by the loop) and consider any special properties you find.
5. This puzzle draws inspiration from a region division puzzle with a four-letter name (rot13 = NENS) that also pairs clues together.

Solution: PDF and solving animation.

Note: Follow this link for other Loop/Path puzzles.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our week-0-discussion thread on the GMPuzzles Discord. If you are not yet part of this Discord community, use this link.

Skyscrapers (Sum) by Murat Can Tonta

Getting started with this difficult Skyscrapers (Sum) puzzle designed by Murat Can Tonta probably requires noting a lot about the two distinct clues in the grid.

Skyscrapers (Sum) by Murat Can Tonta

PDF

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

Theme: Two Consecutive Numbers

Author/Opus: This is the 274th puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Variation of Skyscrapers; each clue represents the sum of the heights of the visible buildings in that direction.

Difficulty: 5 stars

Time Standards (highlight to view): Grandmaster = 9:45, Master = 25:00, Expert = 50:00

Solution: PDF and solving animation.

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.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our week-0-discussion thread on the GMPuzzles Discord. If you are not yet part of this Discord community, use this link.

Arrow Sudoku by Serkan Yürekli

Even though today is not Valentine’s Day, Serkan Yürekli is presenting us with a love-themed Arrow Sudoku and must be drawing attention to our shared love for solving puzzles.

Arrow Sudoku by Serkan Yürekli

PDF

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

Theme: Love

Author/Opus: This is the 451st puzzle from our managing editor Serkan Yürekli.

Rules: Standard Arrow Sudoku rules.

Estimated Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 5:15, Master = 8:35, Expert = 17:10

Solution: PDF and solving animation.

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 these books in our e-store.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our week-0-discussion thread on the GMPuzzles Discord. If you are not yet part of this Discord community, use this link.

Araf by Serkan Yürekli

While it can be difficult to make an Araf puzzle unique, the trick lies in concealing the solving path, which is primarily why Serkan Yürekli’s Araf has a high difficulty level.

Araf by Serkan Yürekli

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 shading mode.)

Theme: Triplets

Author/Opus: This is the 425th puzzle from our managing editor Serkan Yürekli.

Rules: Standard Araf rules.

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:15, Master = 9:00, Expert = 18:00

Solution: PDF and solving animation.

Note: Follow this link for more Araf puzzles on this website. If you are new to this puzzle type, here are our easiest Araf Puzzles to get started on. More Araf puzzles can be found in the ebook Araf by Serkan Yürekli.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Season 2 Preview Week Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access and check subscriber instructions for role-related access.

Consecutive Pairs Sudoku by Akash Doulani

In puzzles where the clue distributions are symmetric, a general concept is that you can often use an approximation for one portion of the puzzle’s symmetry if you have one for the other side. Will this thinking apply to Akash Doulani’s puzzle here?

Consectuive Pairs Sudoku by Akash Doulani

PDF

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

Author/Opus: This is the 16th puzzle from guest contributor Akash Doulani.

Rules: Standard Consecutive Pairs Sudoku rules. (If a gray circle is given between two adjacent cells, then the two numbers in those cells must be consecutive. Note not all gray circles are given; adjacent cells without a circle may contain either consecutive numbers or nonconsecutive numbers.)

Estimated Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 5:30, Master = 7:30, Expert = 15:00

Solution: PDF and solving animation.

Note: Follow this link for Consecutive Pairs Sudoku puzzles on this website. If you are new to this puzzle type, here are our easiest Consecutive Pairs Sudoku to get started on. More Consecutive Pairs Sudoku puzzles can be found in these books in our e-store.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Season 2 Preview Week Discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access and check subscriber instructions for role-related access.

WSC Playoff Puzzle 10/10: Sudoku by Thomas Snyder

The final puzzle for the World Sudoku Championship playoffs is a tricky classic Sudoku with a trophy theme by Thomas Snyder. It was designed to have a narrow solving path at the sticking point, although speed solvers might choose to “bifurcate” to go faster as happened in the competition.

Sudoku by Thomas Snyder

PDF

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

Theme: Trophy

Author/Opus: This is the 457th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules.

Estimated Difficulty: 3.5 stars

Solution: PDF for all playoff puzzles.

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 Sudoku including variations can be found in these books in our e-store.

WSC Playoff Puzzle 9/10: Clone Shape Sudoku by Joseph Howard

The last two closing puzzles of the World Sudoku Championship playoffs were very tricky, starting with this hybrid of Clone and Shape Sudoku by Joseph Howard.

Clone Shape Sudoku by Joseph Howard

PDF

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

Theme: 8 Rings

Author/Opus: This is the 33rd puzzle from guest contributor Joseph Howard.

Rules: Combination of Shape and Clone Sudoku rules. Insert a number from 1 to 9 into each cell so that no number repeats in any row, column, or bold region. Also, there are some numbered shapes that must be put into the grid. Shapes can be rotated, but cannot be reflected. Each shape outside the grid must appear exactly once inside the grid. Also, all remaining shaded regions of the same shape (“clones”) must be able to be paired together to include the same numbers in the same positions.

Estimated Difficulty: 3.5 stars

Solution: PDF for all playoff puzzles.

Note: Follow this link for more variations of Sudoku.

Multiples Sudoku by Thomas Snyder

[This puzzle comes from the 2022 US Sudoku Grand Prix round. Multiples Sudoku was a basic idea I had not seen before in a number placement puzzle, so I decided to use it in this competition structure taking full advantage of the limitations with putting so many eight clues into the grid. It ended up being the hardest puzzle in the competition, but without given numbers I’m not sure there are any “easy” Multiples Sudoku to really construct for solvers.]

Multiples Sudoku by Thomas Snyder

PDF

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

Theme: Too Many Eights?

Author/Opus: This is the 443rd puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules. Also, some numbers are given on the edges between two adjacent cells. Treating those cells as a two-digit number (reading left to right or top to bottom), the two-digit number must be a multiple of the clue. (For example, near a 7 clue, the two digits can be 14, 21, 28, 35, ….)

Estimated Difficulty: 4 stars

Solution: PDF

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

Killer Sudoku by Thomas Snyder

[This puzzle comes from the 2022 US Sudoku Grand Prix round. This Killer Sudoku was one of my favorite constructions even though I don’t write the style too often. I wanted to get a chain of “last-digit eight” clues into a loop in the grid, and managed to find cage sizes that made good use of 8, 18, 28, and 38 values in this grid. While a few given digits were needed to seed the solving path, that did not diminish the unique “eight” theme visually or logically.]

Killer Sudoku by Thomas Snyder

PDF

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

Theme: Eight Ouroboros

Author/Opus: This is the 442nd puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules. Also, the sum of the digits in each cage must equal the value given in the upper-left corner of that cage. Digits cannot repeat inside a cage.

Estimated Difficulty: 3.5 stars

Solution: PDF

Note: Follow this link for more Killer Sudoku and this link for classic Sudoku. More Killer Sudoku puzzles can be found in Killer Sudoku by Serkan Yürekli.

Arrow Sudoku by Thomas Snyder

[This puzzle comes from the 2022 US Sudoku Grand Prix round. This variation again uses a double eights theme, both with two large eight shapes and a pair of given eights. I tried to have several different kinds of arrows used across the two eights, with a key question of should an eight be the sum of one or more of the arrows.]

Arrow Sudoku by Thomas Snyder

PDF

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

Theme: Double Eights

Author/Opus: This is the 441st puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Arrow Sudoku rules.

Estimated Difficulty: 3 stars

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.