Sudoku Variants Series (277) - Double Sandwich Sudoku
(Published on 15. July 2020, 00:00 by Richard)
Double Sandwich Sudoku
Inspiration for this type comes from Christoph Seeliger Sudoku GP 2020 German/Dutch round.
Solve online in Penpa+ (thanks Nick Smirnov!)
Apply classic sudoku rules.
Clues outside the grid indicate the sum of the digit(s) placed between the digits 1, 5 and 9 in the respective row or column. These clues are placed in ascending order. The order of the digits 1, 5 and 9 is not given.
Solution code: Row 1, followed by column 5.
Comments
on 10. November 2021, 17:21 by Richard
Precision of link to solve online.
on 9. November 2021, 00:46 by Nick Smirnov
Penpa (with Sudoku mode available, solving sudokus in Number mode is quite tedious):
https://git.io/JX2G6
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Thanks again Nick!
I read your earlier comment about the unclarity of the rules when I wasn't able to respond, but you found the way yourself!
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@Richard, I went through your link with example and my questions went away. There is a popular saying in Russian: It is better to see something once, then to hear about it one hundred times. Well, it is often the case with sudoku variants rules :D
My online version of the puzzle is also in Penpa, not in f-puzzles (it seems that there is no way for now to make vertical stacks of outside numbers in f-puzzles). SudokuExplorer made the online version when there were no Sudoku mode in Penpa, people solved sudokus using Number mode which is quite tedious because you must do extra mouse clicks when you switch between numbers, center and corner pencilmarks. There is no way to use Sudoku mode in SudokuExplorer's version, so I decided to make a version where Sudoku mode is available.
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Thx Nick; didn't notice that. Fixed now!
on 7. May 2021, 04:05 by RockyRoer
Great fun as always! If any of you haven't had enough of 159 sandwich logic, I've got one for you-- be warned though - I'm not as nice as Richard. I don't give you any given digits! (id=0005I0)
on 6. May 2021, 11:17 by Krokant
It really shows that you are fond of aesthetics. The way you choose your clues is always the cherry on top of already very delicious cakes. :)
on 15. July 2020, 15:47 by Richard
Added link to Penpa.
on 15. July 2020, 11:53 by SudokuExplorer
Here's a penpa link to try it: https://tinyurl.com/y8bdnv8z
I'll have a go now as well.
@SudokuExplorer: thanks! I should learn how to do that too! (But I have to lift the stone I live under first! :-) )
on 15. July 2020, 11:37 by Richard
@henrypijames: you are right about that. As you may have discovered, I am very fond of aesthetics; I use it whenever possible. While setting puzzles, I don't always try to minimize the number of clues, since going over them again and again is really time consuming. And for this one: I know I used the bottom clue relatively early in my solve, so it is very likely the difficulty is influenced by it.
on 15. July 2020, 11:30 by Richard
@kishy72: That's correct!
I received and test solved Christophs puzzle in January or thereabout, found it suitable for the GP, put it aside and wrote 'Double Sandwich' on my SVS-list. I created this one in March, had it tested and put it aside to serve as practice material for the GP. (I had in mind to publish it a few days before the GP.) I realised far too late that the rules for the different puzzles were different when it comes to the order of the clues. So I decided to publish it only after the GP, so players were not confused before the competition. :-)
on 15. July 2020, 11:05 by henrypijames
By the time I arrived at the bottom row, the clues were no longer needed (and they weren't used before that either).
On second thought: They would have made things easier, of course, if I had paid attention...
on 15. July 2020, 10:45 by kishy72
Excellent construction. I initially broke the sudoku after about 6 mins assuming that the rules are exactly the same as the one in the GP until I realized they are not !
