Cave (Diagonal) by Prasanna Seshadri

Cave (Diagonal) by Prasanna Seshadri


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.

Cave (Diagonal) Example by Thomas Snyder

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.

  • egrieg says:

    Is this a new Variant or are there other examples of it? I would like to see more, very fun, though i forgot about the 2×2 rule at first and didn’t make any progress. With the additional rule it seems to me there are a lot of rules to remember, and there were more uses of the checkerboard rule than in a normal cave puzzle.

  • mokrton says:


  • Nick Ellis says:

    Interesting variation. I found the correct answer string, but it seems to me the cell below the 2 on the right edge could have the opposite shading and still be a valid solution under the diagonal rule. Have I made a mistake?

  • Avatar photo drsudoku says:

    Nick: Have you stranded a part of the non-Cave inside the cave by doing that? It may help to see an image of your expected solution but I expect you have violated some of the other Cave rules in doing that change.

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