This week we crossed a milestone with over 2,500 puzzles posted on the web. Alongside this huge number, which has still never included a broken puzzle with 0 or more than 1 solutions, we finished posting solution PDFs for all of our earliest puzzles from 2013 so every web week now has solutions available. We also now have Penpa versions for almost every major style (2350+ puzzles) and mainly have one-off variations to still digitize. So by the time we hit our 10-year anniversary at the end of this year, our archive will be in great shape! If you’ve appreciated our content through the years, please consider buying some of our books (all with original puzzles) or making a donation to help support the site and our authors.

6 of our 2,500+ puzzles coming from this past week, which featured the number placement styles Smashed Sums and Terra X, are gathered in this PDF and the solutions are in this PDF.

The daily solution videos are on the posts and linked below:

This next week will feature Slitherlink and variations, including a Sunday Stumper in one week’s time. Next Sunday we will also be releasing the new book Slitherlink and Variations 2 by Matej Uher, so look forward to a week+ of getting thrown for a loop.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)

Theme: Mystery Box

Author/Opus: This is the 12th puzzle from guest contributor Sam Cappleman-Lynes.

Rules: Place a number from 0 to 9 into each area so that no two areas that touch orthogonally share the same number. Wherever four areas meet at a point (marked with dots as a visual aid), the numbers in those areas must add up to 10.

Also, see this example:

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 14:45, Master = 21:00, Expert = 42:00

Solution: PDF and solving video.

Note: Follow this link for other less common Number Placement puzzles.

PDF

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

Theme: Dominoes

Author/Opus: This is the 239th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Place a number from 0 to 9 into each area so that no two areas that touch orthogonally share the same number. Wherever four areas meet at a point (marked with dots as a visual aid), the numbers in those areas must add up to 10.

Also, see this example:

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:45, Master = 7:00, Expert = 14:00

Solution: PDF and solving video.

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)

Theme: Order and Disorder

Author/Opus: This is the 375th puzzle from our managing editor Serkan Yürekli.

Rules: Fill each row and column of the grid with the digits 1 to 5 and two blackened cells. Numbers outside the grid indicate the sum of the digits between the two blackened cells in that row or column. Blackened cells are allowed to touch. Or see here.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 4:30, Master = 6:30, Expert = 13:00

Solution: PDF and solving video.

Note: Follow this link for other less common Number Placement puzzles.

PDF

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

Theme: 0 to 7

Author/Opus: This is the 53rd puzzle from our contributing puzzlemaster JinHoo Ahn.

Rules: Place a number from 0 to 9 into each area so that no two areas that touch orthogonally share the same number. Wherever four areas meet at a point (marked with dots as a visual aid), the numbers in those areas must add up to 10.

Also, see this example:

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:45, Master = 3:00, Expert = 6:00

Solution: PDF and solving video.

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)

Theme: Even Vs Odd

Author/Opus: This is the 97th puzzle from our contributing puzzlemaster Ashish Kumar.

Rules: Fill each row and column of the grid with the digits 1 to 4 and two blackened cells. Numbers outside the grid indicate the sum of the digits between the two blackened cells in that row or column. Blackened cells are allowed to touch. Or see here.

Difficulty: 2 stars

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

Solution: PDF and solving video.

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)

Theme: Squared Away

Author/Opus: This is the 382nd puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Fill each row and column of the grid with the digits 1 to 4 and two blackened cells. Numbers outside the grid indicate the sum of the digits between the two blackened cells in that row or column. Blackened cells are allowed to touch. Or see here.

Difficulty: 1.5 stars

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

Solution: PDF and solving video.

Note: Follow this link for other less common Number Placement puzzles.

We just released our latest Starter Pack book, Starter Pack 4: Slitherlink by Takeya Saikachi. Like our other Starter Packs, this book contains a great set of elegantly hand-crafted easy-to-medium difficulty puzzles to get started with some of our different puzzle genres. Slitherlink is a loop puzzle style with a lot of depth of logic stemming from its very simple rules, and we’ve featured it a lot on this site. Like our other Starter Packs, all of the puzzles in this book also have a penpa link for digital solving. This book is also the first time we have saved penpa “solving animations” for each puzzle, so you can watch step-by-step how someone can go through the puzzle to get to the final answer which may help solvers know where to look when they get stuck. We are planning to bring Penpa solving tools and these solution animations to more of our upcoming titles, so please share your feedback here.

The new Starter Pack book connects to our most recent “Starter Pack” variety mix week of puzzles which included a Slitherlink by Takeya. Those puzzles are is gathered in this PDF and the solutions are in this PDF.

The daily solution videos are on the posts and linked below:

In the background we’ve been continuing our project to digitize our full puzzle archive for Penpa solution modes. All Sudoku puzzles of any type as well as all Skyscrapers puzzles have now been covered. This week we expect to finish Minesweeper and Battleships too. This will leave us with only a couple main genres and five “Other” categories to go to get nearly every puzzle in our soon-to-be ten year history available for solving in this mode.

This coming week features two different Number Placement styles that I often connect with the World Puzzle Championship: Smashed Sums (aka Doppelblock) and Terra X (which I first saw in 2019 at the last live WPC).

PDF

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

Theme: Lion Face

Author/Opus: This is the 17th puzzle from guest contributor Rajesh Kumar.

Rules: Standard Thermo-Sudoku rules.

Difficulty: 2.5 stars

Time Standards (highlight to view): Grandmaster = 2:45, Master = 5:00, Expert = 10:00

Solution: PDF and solving video.

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in The Art of Sudoku 2 and Masterpiece Sudoku Mix 2.

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: Spiral Galaxy

Author/Opus: This is the 10th puzzle from guest contributor Eric Fox.

Rules: Standard Aqre rules: Shade some cells so that all shaded cells form one connected group. Regions with numbers must contain the indicated count of shaded cells, and it is allowed to shade over the numbered cells. There may not exist a run of four or more consecutive shaded or unshaded cells horizontally or vertically anywhere in the grid.

See also this example:

Difficulty: 2.5 stars

Time Standards (highlight to view): Grandmaster = 2:00, Master = 4:00, Expert = 8:00

Solution: PDF and solving video.

Note: Follow this link for more Aqre puzzles. If you are new to this puzzle type, here are our easiest Aqre to get started on. More Aqre puzzles are in Shading Variety Collection by Prasanna Seshadri.