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.

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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: 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 multiple modes including a shading mode, the linex mode where left click+drag draws lines and right click marks X’s, a shape entry mode, and a number entry mode)

Theme: Logical

Author/Opus: This is the 6th puzzle from guest contributor Roger Barkan.

Rules: Combination of Star Battle and Cave. Place digits into two cells in every row, column, and region of the top grid (one cell in the example). Digits cannot touch, not even diagonally. The numbers in the upper-left of each region indicate the identity of the digit to be entered in that region. The digits must form a valid cave puzzle (which can be solved on the bottom grid).

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 = 9:00, Master = 15:30, Expert = 31:00

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.

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 49th puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Standard Cave rules. Also, an even number of cells in each row and in each column must be inside the cave.

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 = 3:15, Master = 6:30, Expert = 13:00

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.

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 (for patron Veep)

Author/Opus: This is the 125th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Variation of Cave. Number clues give the total count of cells connected diagonally to a numbered cell including the cell itself. Also, there can be no 2×2 area fully inside the cave.

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 = 4:15, Master = 5:45, Expert = 11:30

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.

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 110th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Cave rules. Also there are two windows in the upper left (blue) and lower right (red) of the grid. The cells in the same position in these windows must have the exact opposite shading (i.e., those inside the cave in one window are outside the cave in the other window).

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 = 2:45, Expert = 5:30

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.

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.

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.

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.

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.