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: Clue Symmetry and Logic

Author/Opus: This is the 198th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Standard Cave rules; also, all groups of cells outside the Cave must be formed out of different arrangements of exactly five cells (i.e., different pentominoes). Pentomino shapes may be reflected or rotated, but they cannot repeat or touch each other. Not all pentominoes need to appear.

This example uses four cell regions (i.e., tetrominoes) within the same rules.

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 = 6:45, Master = 11:45, Expert = 23:30

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. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.

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: Easy As …?

Author/Opus: This is the 99th puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Standard Cave rules.

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 = 3:45, Master = 6:45, Expert = 13:30

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. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.

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: Sunken Lake

Author/Opus: This is the 54th puzzle from our contributing puzzlemaster John Bulten.

Rules: This puzzle is a combination of Cross the Streams and Cave rules (with the exception of having multiple “caves” that all connect to the edge of the grid).

Shade some empty cells black to create a single group of black cells that are all connected to each other through their edges. No 2×2 cell area within the grid contains all black cells. Numbers to the left/top of the grid represent the groups of consecutive black cells which are in that row/column in order, either from left to right or from top to bottom. A question mark (?) represents a group of consecutive black cells whose size is unknown; an asterisk (*) represents any number of unknown groups of black cells, including none at all.

All white cells must be connected via other white cells to an edge of the grid. All numbered cells inside the grid must be white and each number in these cells indicates the total count of white cells connected vertically and horizontally to the numbered cell including the cell itself.

See also this example:

Answer String: Enter the length in cells of each of the (white) 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 = 3:30, Master = 4:30, Expert = 9:00

Solution: PDF

Note: Follow this link for other Cross the Streams. Follow this link for other Cave variations and this link for other classic Caves. If you are new to Cave puzzles, here are our easiest Cave Puzzles to get started on. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.

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: Skewed Diagonals

Author/Opus: This is the 168th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Cave rules.

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 = 2:30, Master = 4:15, Expert = 8:30

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. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.

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: Prime and Reason

Author/Opus: This is the 269th puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Standard Cave rules.

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 = 2:45, Expert = 5:30

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. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.

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: Clue Symmetry & Logic

Author/Opus: This is the 268th puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Standard Cave rules.

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 = 1:15, Master = 1:30, Expert = 3:00

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. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.

Here are our best Region Division puzzles of 2017, selected from the 42 web posts in this category (our second most frequent class of puzzle).

One of our theme weeks in 2017 was “Just One” with lots of puzzles using just the clue number 1. This Pentominous puzzle from Carl Worth was a very creative use of the just one rule, featuring the Roman numeral I, and was voted one of our best puzzles.

Another of the top puzzles was this Fillomino variation by Murat Can Tonta that required symmetric regions.

Our best Region Division puzzle of 2017 came from a guest constructor who is now a regular US puzzle team member: Walker Anderson (link to his blog). Walker cracks the “best of” listings a few times this year for his contributions, and this Cave puzzle had a really incredible logical flow.

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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: Clue Symmetry & Logic (prepared for the 2017 Puzzle Grand Prix)

Author/Opus: This is the 279th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Cave rules.

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 = 6:00, Master = 18:00, Expert = 36:00 (*Estimates from competition scoring, not our usual process)

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. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.

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: Diamonds

Author/Opus: This is the 266th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Cave rules.

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 = 3:30, Master = 5:15, Expert = 10:30

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. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.

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: Clue Symmetry and Logic

Author/Opus: This is the 7th puzzle from guest contributor Walker Anderson.

Rules: Standard Cave rules.

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 = 3:45, Master = 8:45, Expert = 17:30

Solution: PDF; a solution video is available here.

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. More Cave puzzles can be found in The Art of Puzzles and in Roger Barkan’s Colossal Cave Collection.