Best of luck and skill to all competitors in Kraków, Poland this week at the World Sudoku and Puzzle Championships (WSPC).

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

Theme: US Team for 2022 World Sudoku and Puzzle Championships

Author/Opus: This is the 424th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: This puzzle from the US team t-shirts for the world championships is originally being released in an “instructionless” mode. It combines a common sudoku variation and a common puzzle type. More info is now available below.

Identity of the two rule sets: (highlight to view): This puzzle combines Thermo-Sudoku and Skyscraper styles. The combination of this style with no givens was first constructed by Thomas Snyder for the 2013 United States Puzzle Championship.

Solution: PDF; the puzzle was featured in a Cracking the Cryptic solving video here.

From Prasanna: “This puzzle is meant to be a culmination of 10 years of authoring puzzles. I want to especially thank GMPuzzles for accommodating these special puzzles every year even if it may not have fit the regular schedules. I also see this puzzle as a “reset” of sorts, and I’ll get back to simple ideas to celebrate my next few birthdays, and then see where that takes me. These last 10 years have been a fantastic experience and I’d like to take this moment to thank the puzzle community as a whole for being a huge part of my journey.”

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or solve online (using our beta test of Penpa-Edit tools; note that the default puzzle info is too long — even for an url shortener — so copy and paste all the text in this file into the “Load” option in the upper-right of the penpa-edit interface to access.)

Theme: The Journey

Author/Opus: This is the 201st puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Please see first two pages of the PDF for a detailed description of the rules and more background on the theme of the puzzle.

Difficulty: 5 stars?

Solution: PDF

(Note: This bonus puzzle is being posted today to mark the occasion of Prasanna’s birthday.)

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or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a shading mode, a line-drawing mode with diagonal and straight options, and an edge marking mode to add x’s as needed.)

Theme: One Away from Thirty

Author/Opus: This is the 180th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Locate two snakes in the grid. Each snake must start from one of the gray circles, but has an unknown ending point. Black circles represent an interior cell of one of the snakes, and all black circles must be part of a snake. Each snake’s path is allowed to move vertically, horizontally, or diagonally between cells. An interior snake cell can only be adjacent to two other snake cells (including diagonally adjacent cells) and an end of the snake can only be adjacent to one other snake cell (including diagonally adjacent cells). The two different snakes must not share any adjacent cells.

There are some numbers outside the grid. These numbers indicate the number of vertical or horizontal edges (not corners) that snakes cross in that direction.

There are some letters inside the grid. For each distinct letter, exactly one of its instances is visited by one of the two snakes.

Also see this example:

Solution: PDF

(Note: this puzzle is like a Sunday Surprise with very high difficulty.)

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Theme: 14 Nisan, 2018 (Pasch 5778)

Author/Opus: This is the 45th puzzle from our contributing puzzlemaster John Bulten.

Rules: See PDF link above for complete rules as well as a solvable example by Thomas Snyder.

Answer String: The solution string is 3 words in ABC order, in all capital letters and separated by commas. (There are a total of 28 letters in this string.)

Time Standards (highlight to view): No time standard (GM time > 2hr).

Solution: Answers for this week in this PDF.

Editor’s Note: The giant grid here is one of the hardest puzzles we have ever presented. If I knew in advance John wanted to make a puzzle like this, I would have said no because of the combination of so many kinds of rules, new puzzle styles, and my expectation it would take hours to solve (and it certainly does!). But there is something inspirational about the elements brought together here by John, many unexpected Ahas that will cure the headaches you’ll also get in the middle. While the giant puzzle was originally created to stand on its own, John added the four medium difficulty puzzles we posted earlier this week to introduce the four subgenres. Be sure to solve these as you prepare for this large test at the end of the week. -TS

Author’s Note: Thanks to Thomas and Grant for encouraging me to construct new puzzle types. Thanks to patron Randy Rogers for requesting 4-grid combination puzzles, which sparked this idea. Thanks to Prasanna for his giant 11/29/15, 3/2/16, and 3/2/17 puzzles, which directly inspired this puzzle. Thanks to Serkan for inventing Light and Shadow, because whenever I tried experimenting with shading puzzles I found myself trying to reinvent Light and Shadow. Thanks to Izak for inventing Surf, which has more potential than either of us realize. Thanks to God for this day. -JB

You can find all the slices of Pi from our most recent week of puzzles in this PDF.

This week we are featuring Pentominous, which is the style of our most recent puzzle e-book “Plenty o’ Pentominous” by Grant Fikes and Murat Can Tonta. If you enjoy this week of puzzles, please get this collection of 52 original puzzles including several 15×15 grids and one giant puzzle.

This week contains a few extras, including two extra puzzles on Friday and Saturday. There is also one easter egg hidden somewhere in this week’s puzzles which, if you find it, will tell you what word to enter here.

Master+ subscribers to the site are getting a bonus Pentominous by Thomas Snyder and a Cave (Pentominous) variation by Serkan Yürekli as well as images of the puzzle solutions. If you want to become a subscriber and get access to bonus puzzles, solutions, e-books, and other rewards, check out this page.

In honor of Kakuro’s past as Cross Sums and Cross Addition, John wanted to share this version of the puzzle with an older presentation style. This presentation may help you find a “hidden puzzle” that John left for solvers to discover.

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Author/Opus: This is the 29th puzzle from our contributing puzzlemaster John Bulten.

Answer String: Enter the fifth row and fifth column of the hidden puzzle solution in standard format, separating the entries with a comma.

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

Solution: PDF

(Note: This bonus puzzle is at a Saturday+ difficulty, and is being posted today to mark the occasion of Prasanna’s birthday.)

(View image directly for larger form.)

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the composite Yajilin mode where left click marks cells, right click marks dots in cells or X’s on edges, left click+drag draws lines.)

Theme: 26 on 03/02

Author/Opus: This is the 152nd puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: This puzzle combines Yajisan-Kazusan with Tapa with additional rules.

Left grid = Yajisan-Kazusan (No 2×2): Shade some cells black so that all unshaded number and arrow clues indicate the exact count of shaded cells in the given direction (all counts extend through gaps in the grid). Shaded cells cannot share an edge, and all white cells must remain connected as part of a single contiguous group. It is allowed to shade over some of the numbered cells; a shaded over clue may or may not be true. Also, no 2×2 area inside the grid can be fully white.

Right grid = Tapa: Shade some empty cells black to create a single connected wall. Numbers in a cell indicate the length of consecutive shaded blocks in the neighboring cells. If there is more than one number in a cell, then there must be at least one white (unshaded) cell between the black cell groups. Cells with numbers cannot be shaded, and the shaded cells cannot form a 2×2 square anywhere in the grid.

Additional rule 1: Clues in the middle of the grids indicate the sum or the difference of the number of shaded cells in that row between the grids (possibly both).

Additional rule 2: The shading of the green outlined regions is equivalent in the two grids in the shared cells (if the cell labeled “A” in the illustration below is shaded in one grid it must be shaded in both grids). Note that the 3 and 2 share all locations except for the bottom vertical stem of the numbers which is shifted.

Answer String: For each marked row, enter the length in cells of each of the unshaded segments from left to right in the Yajisan-Kazusan followed by the length of each of the shaded segments from left to right in the Tapa. Separate each row’s entry from the next with a comma (but do not use commas in between the Yajisan-Kazusan and Tapa entry parts in a given row). Enter both digits for any two-digit large segment in an entry.

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

Solution: PDF

(View image directly for larger form.)

(After solving the puzzle (or before, if you desire) look at this additional image for another challenge.)

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. Note that the default puzzle info is too long — even for an url shortener — so copy and paste all the text in this file into the “Load” option in the upper-right of the penpa-edit interface to access. You can then also open a new tab and copy in all this file for the final additional challenge.)

Theme: Clue Symmetry and Logic

Author/Opus: This is the 100th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: This puzzle combines styles that involve shading cells. All rules are standard for the given puzzle types (Tapa, Light and Shadow, Nurikabe, Kurotto, and Cave) which appear in the indicated spots of the grid (see below).

Tapa: Shade some empty cells black to create a single connected wall. Numbers in a cell indicate the length of consecutive shaded blocks in the neighboring cells. If there is more than one number in a cell, then there must be at least one white (unshaded) cell between the black cell groups. Cells with numbers cannot be shaded, and the shaded cells cannot form a 2×2 square anywhere in the grid.

Cave: (The inside of the cave with the numbered cells is shaded here!) Shade some cells to form a single connected group — the cave — with no enclosed, unshaded cells. In other words, all unshaded cells must be connected by other unshaded cells to an edge of the grid. All numbered cells must be a part of the cave, with each number indicating the total count of cells connected vertically and horizontally to the numbered cell including the cell itself.

Additionally, there are two diamonds made out of cells in each grid. Each cell in the smaller diamond corresponds to two cells in the same position in the larger diamond (see example below). The corresponding cells must differ in their shading (i.e., if a cell in the smaller diamond is shaded, both corresponding cells in the larger diamond are unshaded; if a cell in the smaller diamond is unshaded, both corresponding cells in the larger diamond are shaded).

Answer String: Enter the answer to the additional challenge in ALL CAPITAL LETTERS (no spaces)

Time Standards (highlight to view): Grandmaster = 25:00, Master = 32:30, Expert = 1:05:00

Solution: PDF

Serkan finished this “Giant” puzzle shortly after we started our break. We figured this Gapped Kakuro would be a fun, challenging Sunday Surprise that might take several Sundays to complete.

(view directly for a larger image)

PDF

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

Theme: Sum Time

Author/Opus: This is the 72nd puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Standard Kakuro Rules. Also, some cells may remain empty but empty cells cannot share an edge with other empty cells.

Answer String: Enter the values in the white cells in the marked rows from left to right, ignoring all black cells, and separating the rows with a comma. Use a capital ‘X’ for any blank cell.

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

Solution: PDF

Note: Follow this link for other Kakuro puzzles.

For those who thought there would be no special puzzles on Sundays in 2014: SURPRISE!

This very creative submission comes from Nikolai Beluhov. And like his earlier Matryoshka Fillomino, this is a gift that keeps on giving. Starting with a challenging Fillomino puzzle, erasing all of the 4s leaves a Slitherlink. Then erasing all of the 3s leaves a Tapa. Then erasing all of the 2s gives a Simple Loop (treating the 1s as blackened cells).

PDF

Fillomino

Slitherlink

Tapa

Simple Loop

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between a Composite Edgesub mode for Fillomino and Slitherlink, a shading mode for Tapa, a number entry mode for Fillomino, and a line drawing mode for Simple Loop.)

Rules: Standard Fillomino rules.
Then standard Slitherlink rules.
Then standard Tapa rules.
Then Simple Loop rules (draw a single closed loop, without intersections or crossings, through all empty cells; cells with 1s cannot be visited by the loop).

Answer String: None for this puzzle; simply click solved if finished.

Solution: PDF