Basement Skyscraper Sudoku by Prasanna Seshadri

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Sudoku by Prasanna Seshadri

PDF

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

Theme: Sudoku GP Round 7, plus two hidden themes related to 7
(Note: this puzzle was originally created for the Sudoku Grand Prix but after testing was judged too hard and too puzzle-based for the competition. It is an excellent puzzle, and we are proud to showcase it here.)

Author/Opus: This is the 40th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Standard Sudoku rules. Also, standard Skyscrapers rules. Additionally, the cells in gray are “underground” and cannot be seen by any of the outside skyscraper clues (think of them as starting with a negative sign if necessary). As an example, the 3 on the left of row 2 refers only to seeing three buildings in columns 2 through 9, even if there is a 9 in column 1 as that 9 cannot be seen.

Answer String: Enter the 1st row from left to right, followed by a comma, followed by the 5th row from left to right.

Time Standards (highlight to view): Grandmaster = 7:00, Master = 10:00, Expert = 20:00

Solution: PDF

Note: Follow this link for our first Basement Skyscraper Sudoku. Follow this link for other less common variations of Sudoku and this link for classic Sudoku. If you are new to this puzzle type, here are our easiest Sudoku to get started on.

  • That was really elegant! The skyscrapers with the basement spaces combined to make some lovely deductions early on in the solve rather than just the usual sort of “is this 26 or 62 to get my skyscraper to have the right value” kinds of things. In fact in a lot of ways it solved more like a skyscraper than a sudoku, though the box constraints came up a lot. Anyway, beautiful puzzle. Would solve again.

  • drsudoku says:

    “In fact in a lot of ways it solved more like a skyscraper than a sudoku” – this was exactly the problem I faced in judging if it should be part of the Sudoku GP series. It is an incredible puzzle for all the reasons you bring up.

  • skynet says:

    12:15!

  • BeautyOfConfigurations says:

    29 minutes, nice concept !! One can attain artistic pleasure while solving this unlike the mental harassment one goes through while solving computer generated stuff !

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