PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between Sudoku = big digits and Number candidate = small entries in the corners of cells.)

Theme: Equal Distribution and Pairing of Clue Numbers

Author/Opus: This is the 4th puzzle from guest contributor Roland Voigt.

Rules: Standard Skyscrapers rules. Also, some cells have been split into triangles, each of which must be filled with a number. In this puzzle, the numbers 1-6 must be placed in each row and column.

(The split cells are viewed in the order they are seen from a given direction, so the upper triangles are seen first from the left/top sides and the bottom triangles are seen first from the right/bottom sides.)

Answer String: Enter the 1st row from left to right, followed by a comma, followed by the 5th row from left to right. Enter the split cells in the order they are seen from the left (the upper triangle before the lower triangle).

Time Standards (highlight to view): Grandmaster = 2:00, Master = 2:40, Expert = 5:20

Solution: PDF

Note: Follow this link for other classic Skyscrapers and this link for variations on Skyscrapers puzzles. If you are new to this puzzle type, here are our easiest Skyscrapers to get started on.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between Sudoku = big digits and Number candidate = small entries in the corners of cells.)

Theme: Equal Distribution and Symmetry of Clue Numbers

Author/Opus: This is the 2nd puzzle from guest contributor Roland Voigt.

Rules: Standard Skyscrapers rules. Also, some cells have been split into triangles, each of which must be filled with a number. In this puzzle, the numbers 1-5 must be placed in each row and column.

(The split cells are viewed in the order they are seen from a given direction, so the upper triangles are seen first from the left/top sides and the bottom triangles are seen first from the right/bottom sides.)

Answer String: Enter the 1st row from left to right, followed by a comma, followed by the 3rd row from left to right. Enter the split cells in the order they are seen from the left (the upper triangle before the lower triangle).

Time Standards (highlight to view): Grandmaster = 0:40, Master = 1:15, Expert = 2:30

Solution: PDF

Note: Follow this link for other classic Skyscrapers and this link for variations on Skyscrapers puzzles. If you are new to this puzzle type, here are our easiest Skyscrapers to get started on.

PDF

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

Theme: Going Up?

Author/Opus: This is the 171st puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Variant of Skyscrapers rules. The numbers outside the grid represent the sum of the buildings seen in that row or column. For example, if a row is 12534, the clue from the left would be an 8 (1+2+5) and from the right would be a 9 (4+5).

Answer String: Enter the 3rd row from left to right, followed by a comma, followed by the 7th row from left to right.

Time Standards (highlight to view): Grandmaster = 3:15, Master = 4:30, Expert = 9:00

Solution: PDF

Note: Follow this link for classic Skyscrapers puzzles and this link for variations on Skyscrapers puzzles. If you are new to this puzzle type, here are our easiest Skyscrapers Puzzles to get started on.

I’m sure many of you were expecting ANOTHER version of the Christmas Tree puzzle from the last two weeks. I mean, I did get a very nice Double Back from Robert Vollmert (which cannot be confused as a Star Battle or a LITS). But posting such a puzzle wouldn’t be a surprise.

No, today’s Sunday Surprise comes from the pile of submissions I’ve received over the year from Hans van Stippent, who played with the usual rules of Skyscrapers a bit by hiding some of the cells from consideration. It yielded a very interesting puzzle which is Hans’ gift to you this Sunday.

PDF

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Theme: New Variation/Logic

Rules: Standard Sudoku rules. Also, standard Skyscrapers rules. Additionally, the cells in gray are “underground” and cannot be seen for any of the outside skyscraper clues (think of them as starting with a negative sign if necessary). As an example, the 4 in row 2 refers only to seeing four buildings in columns 3 through 7, even if there is a 9 in column 1 or column 2 as that 9 cannot be seen.

Answer String: Enter the 1st row from left to right, followed by a comma, followed by the 9th row from left to right.

Solution: PDF

PDF

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

Theme: Nine High

Rules: Variant of Skyscrapers rules. The numbers outside the grid represent the sum of the buildings seen in that row or column. For example, if a row is 12534, the clue from the left would be an 8 (1+2+5) and from the right would be a 9 (4+5).

Answer String: Enter the 2nd row from left to right, followed by a comma, followed by the 5th row from left to right.

Time Standards (highlight to view): Grandmaster = 1:00, Master = 2:15, Expert = 4:30

Solution: PDF

PDF

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

Theme: Clue Symmetry and Logic

Rules: Variation of Skyscrapers rules. Place digits 1-6 into the grid so that no digit is repeated within a row or column. Digits outside the grid indicate the number of buildings that can be seen from the corresponding direction. The buildings form two-digit numbers and the relations between some numbers are shown with a greater than/less than sign.

Or, see here.

Answer String: Enter the 3rd row from left to right, followed by a comma, followed by the 4th column from top to bottom.

Time Standards (highlight to view): Grandmaster = 5:15, Master = 7:30, Expert = 15:00

Solution: PDF

PDF

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

Theme: Clue Symmetry and Logic

Rules: Variation of Skyscrapers rules. Place digits 1-6 into the grid so that no digit is repeated within a row or column. Digits outside the grid indicate the number of buildings that can be seen from the corresponding direction. The buildings form two-digit numbers and the relations between some numbers are shown with a greater than/less than sign.

Or, see here.

Answer String: Enter the 2nd row from left to right, followed by a comma, followed by the 4th row from left to right.

Time Standards (highlight to view): Grandmaster = 2:15, Master = 3:15, Expert = 6:30

Solution: PDF

PDF

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

This is a “Franken-Friday” puzzle variation.

Theme: Logical

Rules: Standard Skyscrapers rules. Also, the digits do not repeat along the two main diagonals.

Answer String: Enter the 3rd row from left to right, followed by a comma, followed by the 4th row from left to right.

Time Standards (highlight to view): Grandmaster = 3:30, Master = 5:15, Expert = 10:30

Solution: PDF

As promised, here was the original Thermo-Skyscrapers created for the USPC. I like the visual pattern and tightness of solving path much more, but it was simply too hard to use, particularly before the practice you now have from the one you saw on the USPC from yesterday’s post.

PDF

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Theme: No given numbers, and full clue cell symmetry

Rules: Standard Skyscrapers rules. Also, as in Thermo-Sudoku, digits must be strictly increasing in all thermometer shapes from round bulb to flat end.

Answer String: Enter the seven digits inside the grid for the 7th row from left to right, followed by a comma, and then the seven digits inside the grid for the 4th column from top to bottom.

Solution: PDF

The hardest puzzle I wrote for the USPC was originally intended to be presented as a subtle “surprise”. The rules would have covered what thermometer shapes do (strictly increase from bulb to flat end), but would not have been explicit that those shapes could reach outside the grid. So finding a grid with no external numbers but with many external shapes would have been a manageable but perhaps unexpected surprise. But it was decided to just be explicit here, and with some other authors in the last few months having used the same external clue ideas with skyscrapers (including myself here with an Even/Odd Skyscrapers after I knew the fate of this puzzle) it’s not clear if this would have been unexpected anyway.

I thought this was an interesting extension of some inequality skyscraper concepts I’ve seen elsewhere. My first attempt at this puzzle type was judged very elegant and far too hard. My second attempt kept one of these two traits and made it onto the test. Like the TomTom, this variation seemed to get pretty good reviews, but I do know some solvers who fell into the trap of thinking an outside number blocked that number from appearing inside the grid.

PDF

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

Theme: No given numbers, and full clue cell symmetry

Rules: Standard Skyscrapers rules. Also, as in Thermo-Sudoku, digits must be strictly increasing in all thermometer shapes from round bulb to flat end.

Answer String: For the USPC, the answer string was the internal cells in the 4th row and 7th row. For this week, you can just hit the solved button on an honor system if you think you’ve solved it.

Solution: PDF