### Cave (Product) by Thomas Snyder

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)

Theme: Powers of Two

Author/Opus: This is the 411th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Variation of Cave rules. Each clue represents the product of the # of row cells visible (including the cell itself) with the # of column cells visible (including the cell itself).

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 4:00, Master = 5:45, Expert = 11:30

Solution: PDF and solving video.

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

### Cave (Product) by Grant Fikes

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)

Theme: 2014 to 2015

Author/Opus: This is the 157th puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Variation of Cave rules. Each clue represents the product of the # of row cells visible (including the cell itself) with the # of column cells visible (including the cell itself).

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 1:30, Master = 2:15, Expert = 4:30

Solution: PDF

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

### Cave (Product) by Thomas Snyder

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)

Theme: Even Slashes

Author/Opus: This is the 156th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Variation of Cave rules. Each clue represents the product of the # of row cells visible (including the cell itself) with the # of column cells visible (including the cell itself).

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 7:30, Master = 13:30, Expert = 27:00

Solution: PDF

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

### Cave (Product) by Prasanna Seshadri

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)

Theme: Logical

Author/Opus: This is the 9th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Variation of Cave rules. Each clue represents the product of the # of row cells visible (including the cell itself) with the # of column cells visible (including the cell itself).

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 2:00, Master = 4:30, Expert = 9:00

Solution: PDF

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

### Cave (Product) by Grant Fikes

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)

Theme: Not Quite Even

Author/Opus: This is the 81st puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Variation of Cave rules. Each clue represents the product of the # of row cells visible (including the cell itself) with the # of column cells visible (including the cell itself).

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 1:45, Master = 3:15, Expert = 6:30

Solution: PDF

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

### Dr. Sudoku Prescribes #71 – Cave (Product)

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)

This is a “Franken-Friday” puzzle variation.

Theme: Common Products

Rules: Variation of Cave rules. Each clue represents the product of the # of row cells visible (including the cell itself) with the # of column cells visible (including the cell itself).

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 3:00, Master = 4:45, Expert = 9:30

Solution: PDF

Note: Follow this link for other classic Caves. If you are new to this puzzle type, here are our easiest Cave Puzzles to get started on.

### Best of 2014: Region Division Puzzles

Region Division puzzles made up a total of 64 posts, and had some of the highest rankings of all of our puzzles making this an incredibly tight category.

One puzzle with a very high FAVE/solver ratio was this creative “Infinity!” Araf from Serkan Yürekli:

(view image directly for larger form)

While many of our best Cave puzzles were contained in our ebooks this year, Thomas Snyder’s Product Cave from January garnered a lot of Favorite votes:

Fillomino puzzles closed out our favorites of 2014. Arguably the best puzzle of the year was a giant Fillomino “Dear John” from Grant Fikes that went out to our patrons in April; these votes just cover our web puzzles though.

Tapio Saarinen made a cute Fillomino out of just tiny digits:

Guest contributor Robert Vollmert created a really challenging Checkered Fillomino with some interesting discoveries inside as well:

Closing out the best Region Division puzzles of 2014 were a pair of Cipher Fillomino from Palmer Mebane. Palmer’s not had a lot of interest in puzzle construction over the last couple years, but whenever he returns with new ideas they have been fantastic. Quoting from his email that submitted these two: “This is not really a return; just a couple good ideas that were too good (in my head) to leave undone.” While Tic-Tac-Toe got a lot of Fave votes, the C Major theme earned the most for Region Division puzzles and tied (with the TomTomTom and a puzzle to be named tomorrow) for Puzzle of the Year:

These best puzzles have been gathered in this PDF.

### New E-Book, Sunday Update, and Solutions

We’ve just published our second Starter Pack, this one by Serkan Yürekli features 30 easy-to-medium Tapa puzzles for solvers getting started with this shading puzzle style. There is a page with penpa-edit links for all thirty puzzles for solvers that want to try these Tapa puzzles out online. Our upcoming week of puzzles will feature six puzzles with “starter pack” type difficulty from six different genres including Tapa.

Our past week of Cave puzzles is in this PDF and the solutions are in this PDF. More Cave puzzles can be found in our store.

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

### Wrapping up 2021 and prepping for 2022

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.

### New e-book: Grandmaster Puzzles Quarterly: Volume 2

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)