Double Dutch Sudoku Advent (23) - Palindrome vs. Coast to Coast
(Published on 23. December 2014, 12:00 by Richard)
Eisbär (Arvid) and I have created a fresh sudoku advent calendar in which we combine a well known variant with a relatively unknown variant every day. Combining variants leads to interesting and surprising new solving techniques.
Logically solvable
All puzzles can be solved completely logically although the logic is sometimes well hidden and is inherent to the combination of restrictions that the different types offer. For that reason we have written some solving hints for most of the puzzles, published in a very tiny font. If you want to read the hints, simply copy these in a text editor and enlarge the font size.
Thank you Gabi!
Gabi (ibag) has translated all advent puzzles, including the solving hints. She also test-solved all puzzles, so at this place we would like to say to you: THANK YOU!!!
Palindrome
Place the digits from 1 to 9 in every row, column and 3x3-block. The numbers on the grey line form a palindromic sequence from one end to the other.
Coast to Coast
The digits outside the grid are in mirrored position in the first three cells from the left and from the right (if one digit is in the second cell from the left, the other digit has to be in the second cell from the right).
Solving hints
R1C8 = R3C6 = 2; R1C2 = 6
R4: 2 not in C1 (this would force a 6 in R4C9 and also in R9C4 which is not allowed), not in C2, C3, C7 or C8. :=> R4C9 = 2; R9C4 = 2; R4C1 = 6
All 2’s can be placed; 9 in R8C3
6 in R9C3 + R8C4; 3 in R9C7
R5C7 cannot be 3 or 7; Coast to Coast pair {37} in R5 in R5C28 and also in R28C5.
6 in R3C5
1 not in R6C123 and not in R6C7 since 8 can’t be in R8C1. 1 in R6C89; 8 in R6 in R6C12.
8 in block top left in R2C3; 1 in R2C7
Solution code: Column 4, followed by column 6.
Comments
on 4. October 2022, 18:49 by Krokant
Well, seems I'm two months early and eight years late at the same time. :)
These are some old puzzles, yes, but I had a ton of fun solving them. So (slightly) belated thanks for making this Advent calendar, Arvid and Richard.
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@Krokant: thanks for your ongoing nice comments to my (and in this case also Arvid's) sudokus! That is really appreciated.
Glad you liked the whole series! :-)
on 11. April 2022, 21:50 by Nick Smirnov
Penpa:
https://tinyurl.com/ycgxojjk
on 5. June 2017, 09:19 by Saskia
schoene idee :)
on 19. May 2015, 16:39 by RobertBe
Arvid and Richard, thank you very much for such a nice series!
on 23. December 2014, 14:26 by pin7guin
Was laut Liste morgen kommen müsste, ist mir klar.
Aber wann kommt das Rätsel, das ALLE diese Varianten in sich vereint? ;-) ;-) ;-)
on 23. December 2014, 13:15 by Eisbär
OK puzzlers... if you paid attention you all know what's coming next (tomorrow) :-D
