[This is a repost from our archives with new notes at the top (original post here): Sometimes it is hard to understand when a clue in an Outside Sudoku is very necessary, somewhat necessary, or superfluous. With a few different themes overlapping in this puzzle (including Fibonacci numbers, multiples of 2, and cubes) the important thing will be to make out how to “use” each clue even if that does not mean putting in sure placements yet.]

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between Sudoku entry modes and a shading mode to mark off clues.)

Theme: A series of series (and a constant and a square) — The seemingly random numbers outside the grid actually have some rhyme and reason.

Rules: Standard Outside Sudoku rules.

Estimated Difficulty*: 3 stars

Time Standards (highlight to view): Grandmaster = 4:00, Master = 7:15, Expert = 14:30

Solution: PDF

Note: Follow this link for more Outside Sudoku puzzles. More Outside Sudoku puzzles can be found in Masterpiece Sudoku Mix 4.

[This is a repost from our archives with new notes at the top (original post here): This very memorable Skyscrapers started by thinking about placing a lot of twos and placing a lot of “bigger than twos”. The puzzle got an extra level of attention in a “How to Build a City” post describing the construction/intended solution path at the same time which many people point to as one of their favorite early posts on the site. This style of general logic puzzle design is covered extensively in Puzzlecraft: How to Make Every Kind of Puzzle for those who want to practice making grandmaster puzzles for themselves.]

PDF

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

Theme: Either/or — a hard solving theme despite so many clues.

Rules: Standard Skyscrapers rules.

Estimated Difficulty*: 2.5 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 5:30, Expert = 11:00

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.

[This is a repost from our archives with new notes at the top (original post here): While Outside Sudoku is a simple concept to understand (all the outside digits work like placement notes for the first three cells in that direction), making thematically interesting puzzles is more challenging. This puzzle started by placing the four big 1-9 nonets outside the grid and then finding an interesting set of deductions on the other edges of the grid to get to one solution.]

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between Sudoku entry modes and a shading mode to mark off clues.)

Theme: Four Nonets

Rules: Standard Outside Sudoku rules.

Estimated Difficulty*: 2 stars

Time Standards (highlight to view): Grandmaster = 2:15, Master = 3:30, Expert = 7:00

Solution: PDF

Note: Follow this link for more Outside Sudoku puzzles. More Outside Sudoku puzzles can be found in Masterpiece Sudoku Mix 4.

[This is a repost from our archives with new notes at the top (original post here): Skyscrapers is a Japanese puzzle style and one of the first genres shared with the world via the World Puzzle Championship as an early mainstay. This first Skyscrapers on Grandmaster Puzzles tries to set up a lot of the logic in the horizontal row clues with the other clues then supporting a path to the unique solution.]

PDF

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

Theme: A little of everything — the rows have clues from 1 to 6.

Rules: Standard Skyscrapers rules.

Estimated Difficulty*: 1.5 stars

Time Standards (highlight to view): Grandmaster = 0:50, Master = 1:30, Expert = 3:00

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.

I’ve been doing some traveling so am a bit late in announcing the release of our fifth episode of Smashing the Sudoku, as we look back at the good (and evil?) sides of puzzle styles like Consecutive Sudoku and Masyu.

We’ve also now completed adding hints and solutions to the four Microsoft Puzzlehunt puzzles we’ve put here over recent Sundays. If you haven’t checked out these puzzles yet please find them alongside a few other “puzzle hunt” puzzles on our blog.

[This is a repost from our archives with new notes at the top (original post here): This very difficult Consecutive Sudoku reveals the two sides of this genre (the positive rule for consecutive digits and the negative “anti”-rule for nonconsecutive digits) with a narrow solving path to connect the top and the bottom.

PDF

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

Theme: Jekyll and Hyde – digits but no bars up top, bars but no digits down below. Master both sides to solve this puzzle.

Rules: Standard Consecutive Sudoku rules.

Estimated Difficulty*: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:30, Master = 9:00, Expert = 18:00

Solution: PDF and solving video.

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

[This is a repost from our archives with new notes at the top (original post here): The first set of Masyu puzzles ends with a grid that almost has “twisted” symmetry meaning antisymmetry of white and black circles. Several less conventional steps are required to find the one true loop in this challenging Masyu.]

PDF

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)

Theme: Almost Twisted! – Slightly imperfect, but more difficult as a result.

Rules: Standard Masyu rules.

Estimated Difficulty*: 2.5 stars

Time Standards (highlight to view): Grandmaster = 1:30, Master = 2:30, Expert = 5:00

Solution: PDF and solving video; advice on solving this puzzle was also posted in “Ask Dr. Sudoku #5“.

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

[This is a repost from our archives with new notes at the top (original post here): In this second Consecutive Sudoku from our first month of puzzles, the “boxes” theme works across four sets of numbers and two consecutive bar groups. Those elements should get you started, but some of the key solving may also occur in the less orderly corners where large runs of digits are implied by the bars and others by the absence of bars.

PDF

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

Theme: Boxes upon Boxes

Rules: Standard Consecutive Sudoku rules.

Estimated Difficulty*: 3 stars

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

Solution: PDF

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

[This is a repost from our archives with new notes at the top (original post here): Making images of smiley faces in puzzle form is one way I try to make the world at least 1% happier. This Wednesday Masyu has a couple less common lookahead steps but should continue to be a good introduction to the genre for those without much prior familiarity (this was a bigger gap in 2013 when the puzzle was written than in 2023).]

PDF

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)

Theme: Smiley Face – our first (but probably not last) use of this theme here.

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

Several members of the GMPuzzles family are from Turkey, and our thoughts go out to them and to others from Turkey and Syria who may have been affected or may know those affected by the recent earthquakes on the Turkish/Syrian border.

GMPuzzles will be donating all proceeds from book sales for the next ten days to relief efforts like those of the Turkish Red Crescent; we will also match any donations that come in via PayPal over the same period (see Tip Jar in left menu). As an advance against those amounts, we’ve given $1,000 to https://ahbap.org/disasters-turkey.

Update 12 Feb 2023: Serkan has constructed a puzzle to help raise awareness and funding for those impacted by the earthquake. We’ve put together this simplified PDF to be able to play along with the puzzle.

The puzzle was also featured on Cracking the Cryptic:

with this link to play the puzzle online.