Dr. Sudoku Prescribes #81 – Battleships

Battleships by Thomas Snyder


or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between ship placement and shading modes. In ship placement mode, right click gives sea, left click gives circle/square, left click and drag for rounded ships.)

Theme: X Marks the Spot

Rules: Standard Battleships rules. Notice the larger than usual fleet beneath the puzzle.

Answer String: For each row from top to bottom, enter the number of the first column from the left where a ship segment appears. If the row is empty, enter 0. Enter these numbers as a single string with no separators.

Time Standards (highlight to view): Grandmaster = 5:45, Master = 8:30, Expert = 17:00

Solution: PDF

  • chaotic_iak says:


    It’s pretty interesting. There are so many uses of “largest ship” trick; I count two. (Yes, that’s many. Usually you only have one.) The 15-ship fleet is interesting to toy with too. The theme is appealing, especially when I note that the givens are symmetrical.

    Now to figure out whether it’s possible to pack the 15-ship fleet to a 10×10 grid (it’s possible; it’s possible with 9×9, even) and to make a good puzzle with it…

  • Aaron Chan says:

    I would want to see the intended solution path to this. I ended up doing a bit of trial and error to deduce that the 5 ship is vertical, then reasoned that the top left is a 4 ship. Then, some diagonal 2-cell type of reasoning deduced that the 2nd row cannot contain a 4 ship. After that, two screws ups, and a lot of time later, I finally cracked it. It was messy, and I am not sure whether there’s a better way to do things.

  • Anuraag Sahay says:

    Very nice puzzle.Deduced the 5-ship’s location soon, but I managed a minute more than expert time on this puzzle.

  • skynet says:

    very nice puzzle.Had great fun solving the puzzle.During solve i was constantly asking myself searching questions of where the 4 segment ships would go if the 5 segmenter is placed in such a way and similarly of where the 3 segment ships would go if the 4 segments are placed.It helped me a lot.

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