
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: Noah’s Ark
Author/Opus: This is the 9th puzzle from guest contributor Roger Barkan.
Rules: Standard Cave rules.
Difficulty: 4 stars
Time Standards (highlight to view): Grandmaster = 5:45, Master = 9:15, Expert = 18:30
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.

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: Sevens
Author/Opus: This is the 7th puzzle from guest contributor Michael Tang.
Rules: Standard Cave rules.
Difficulty: 3 stars
Time Standards (highlight to view): Grandmaster = 3:00, Master = 4:15, Expert = 8:30
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.

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: Mirror Cave
Author/Opus: This is the 386th puzzle from Thomas Snyder, aka Dr. Sudoku.
Rules: Standard Cave rules.
Difficulty: 3 stars
Time Standards (highlight to view): Grandmaster = 2:45, Master = 4:15, Expert = 8:30
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.

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.

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
Author/Opus: This is the 8th puzzle from guest contributor Roger Barkan.
Rules: Standard Cave rules.
Difficulty: 2.5 stars
Time Standards (highlight to view): Grandmaster = 1:45, Master = 3:00, Expert = 6:00
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.

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: Fan
Author/Opus: This is the 7th puzzle from guest contributor William Hu.
Rules: Standard Cave rules.
Difficulty: 1 star
Time Standards (highlight to view): Grandmaster = 0:45, Master = 1:00, Expert = 2:00
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.
This year, we have started to have some extra difficult Sunday Stumpers, about once a month. These will be quite tough puzzles, but with a logical path to be found (and solution videos to help). This sixth Sunday Stumper is a Kakuro puzzle with some extra clue shadings to indicate connected digit subsets for some of the entries.

or solve online (using our beta test of Penpa-Edit tools)
Theme: Eye
Author/Opus: This is the 209th puzzle from our contributing puzzlemaster Prasanna Seshadri.
Rules: Standard Kakuro Rules. Also, whenever two multi-digit entries intersect and the set of digits in one entry is a subset of the set of digits in the other entry, the cell preceding each of those entries (either giving the entry’s clue or indicating that the entry is unclued) is shaded in gray. A shaded cell may be shaded because of its Across entry, Down entry, or both. Any clue cell that is not shaded does not have a multi-digit entry intersecting its Across or Down entries with a shared subset of digits. Any set of digits is considered a subset of itself.
See also this example:

Difficulty: 5 stars
Time Standards (highlight to view): Grandmaster = 20:00, Master = 30:00, Expert = 1:00:00
Solution: PDF; a solution video is also available here.
Note: Follow this link for classic Kakuro and this link for Kakuro variations. More Kakuro puzzles can be found in Kakuro and Variations by Serkan Yürekli and in The Art of Puzzles 2.

or solve online (using our beta test of Penpa-Edit tools)
Theme: Two Snakes
Author/Opus: This is the 72nd puzzle from our contributing puzzlemaster Ashish Kumar.
Rules: Standard Sudoku rules.
Difficulty: 4 stars
Time Standards (highlight to view): Grandmaster = 6:30, Master = 10:15, Expert = 20:30
Solution: PDF; a solution video is also available here.
Note: Follow this link for other classic Sudoku. If you are new to this puzzle type, here are our easiest Sudoku to get started on. More classic Sudoku puzzles can be found in The Art of Sudoku, The Art of Sudoku 2 and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.