So last week was a week at sea for the solvers with Battleships and Battleship Sudoku. It was also my first week at SEA(ttle). And while it already feels like home I have a lot of apartment set-up to do still, and a growing pile of work as I take time to buy and build furniture.

My most observant solvers may have noticed I’ve been following particular genres in YRBGW order so far with my puzzle styles. If you don’t know what I mean, search the website a bit more. But I hate being predictable. I wrote a championship “Trophy” sudoku puzzle once with a first row ?2345678?. My occasional partner in puzzle-solving crime, Wei-Hwa Huang, saw that pattern and thought it was as likely that I would do 923456781 in a competition as 123456789 just to be sneaky. This week, I’ve decided I’ll just flip a coin to determine what I’ll post of the remaining options so you can’t possibly know better than 50:50 what puzzle type is coming. Or maybe that last sentence is a lie. Or maybe every other sentence in this paragraph is a lie. In all honesty, there are no hidden puzzles in this paragraph. But there are two more puzzle styles to come this week: a familiar sudoku style from me and Wei-Hwa, and whichever of “heads” or “tails” wins the coin toss today.

This week I’m going to start hiding the solving times behind a spoiler tag. I don’t know how choosing to see these times before starting will affect your solving, but I’d welcome a discussion on how times, or “points” on a competitive test, change your solving style. Does this differ when you have hand-crafted puzzles with a particular time goal versus, say, a generated croco-puzzle with a particular time standard set from other solvers?

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between number placement, ship placement, and shading modes. The shading mode in gray, which numbers can be written on top of, may work better than default ship placement.)

Theme: Twister

Rules: Standard Battleship Sudoku rules.

Answer String: Enter the 2nd row from left to right, followed by a comma, followed by the 8th row from left to right.

Time Standard: Battleship Sudoku Grandmaster = 6:30, Master = 10:30, Expert = 21:00

Solution: PDF

PDF

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: The Bermuda Quadrangle? The missing radar clues will complicate the solve.

Rules: Standard Battleships rules.

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 Standard: Battleships Grandmaster = 3:45, Master = 7:00, Expert = 14:00

Solution: PDF

Note: Advice on solving this puzzle has now been posted in “Ask Dr. Sudoku #8“

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between number placement, ship placement, and shading modes. The shading mode in gray, which numbers can be written on top of, may work better than default ship placement.)

Theme: Four Islands

Rules: Standard Battleship Sudoku rules.

Answer String: Enter the 8th row from left to right, followed by a comma, followed by the 6th column from top to bottom.

Time Standard: Battleship Sudoku Grandmaster = 5:30, Master = 8:00, Expert = 16:00

Solution: PDF

Note: Advice on solving this puzzle has now been posted in “Ask Dr. Sudoku #8“

PDF

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: Just Try Two Find Us

Rules: Standard Battleships rules.

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 Standard: Battleships Grandmaster = 1:45, Master = 2:45, Expert = 5:30

Solution: PDF

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between number placement, ship placement, and shading modes. The shading mode in gray, which numbers can be written on top of, may work better than default ship placement.)

Theme: Even Steven; the fleet has only certain kinds of numbers.

Rules: Standard Battleship Sudoku rules.

Answer String: Enter the 2nd row from left to right, followed by a comma, followed by the 6th column from top to bottom.

Time Standard: Battleship Sudoku Grandmaster = 1:30, Master = 2:15, Expert = 4:30

Solution: PDF

PDF

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: Rising or Falling? Patterned digits in the rows.

Rules: Standard Battleships rules.

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 Standard: Battleships Grandmaster = 1:00, Master = 1:30, Expert = 3:00

Solution: PDF

There is no Doctor’s Note this week.

Seventh in a series with puzzle solving tips. This time with advice on exploring unusual puzzle geometries such as the Saturday Sudo-Kurve.

When you’ve solved enough 3d Sudoku or Sudo-Kurve puzzles or other unique geometries (as in Sudoku Masterpieces), you’ve probably recognized there are sometimes cells or sets of cells that are much more constrained than others in the construction. This Sudo-Kurve grid, which I used in Sudoku Cup 3 and only one other time since, has some secrets to observe before getting too deep into any puzzle.

(more…)

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Totally Twisted: a challenging grid shape

Rules: Standard Sudo-Kurve rules.

Answer String: Enter the “row” marked A, followed by a comma, followed by the “row” marked B.

Time Standard: Sudo-Kurve Grandmaster = 9:00, Master = 15:00, Expert = 30:00

Solution: PDF

Note: Advice on solving this puzzle has now been posted in “Ask Dr. Sudoku #7”

(View image directly for larger form.)

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the composite Yajilin mode where left click marks cells, right click marks dots in cells or X’s on edges, left click+drag draws lines.)

Theme: Block Party — repeated clues in each corner.

Rules: Standard Tapa rules.

Answer String: Enter the length in cells of each of the shaded segments from left to right for the marked rows, starting at the top. Separate each row’s entry from the next with a comma.

Time Standard: Tapa Grandmaster = 4:30, Master = 7:30, Expert = 15:00

Solution: PDF