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.

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: Central Diamond

Author/Opus: This is the 1st puzzle from guest contributor Chandrachud Nanduri.

Rules: Standard Cave rules. (The puzzle is on a hexagonal grid and cells now see in a maximum of six possible directions.)

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 5:00, Master = 6:15, Expert = 12:30

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.

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: All Threes

Author/Opus: This is the 27th puzzle from guest contributor Joseph Howard.

Rules: Standard Cave rules. (The puzzle is on a hexagonal grid and cells now see in a maximum of six possible directions.)

Difficulty: 2.5 stars

Time Standards (highlight to view): Grandmaster = 2:15, Master = 3:15, Expert = 6:30

Solution: PDF; a solution video is also available here.

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.

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: Knight Steps

Author/Opus: This is the 15th puzzle from our new contributing puzzlemaster JinHoo Ahn.

Rules: Variation of Cave rules. Instead of their usual meaning, interior clues indicate the number of shaded cells in neighboring cells, including diagonally adjacent cells. Cells with numbers cannot be shaded.

See also this example:

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 4:00, Master = 5:15, Expert = 10:30

Solution: PDF; a solution video (with info on an Easter Egg for this puzzle) is also available here.

Note: Follow this link for other 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.

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: 3×3 Squares

Author/Opus: This is the 189th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Cave rules. Also, exactly one digit is a joker wherever it appears; each instance of it may be replaced by any nonzero number, like a “?” clue.

Difficulty: 3 stars

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

Solution: PDF

Note: Follow this link for other 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.

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 264th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Standard Cave rules. (The puzzle is on a hexagonal grid and cells now see in a maximum of six possible directions.)

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 = 4:45, 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 Roger Barkan’s Colossal Cave Collection, in The Art of Puzzles, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

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.