Double Dutch Sudoku Advent (24) - Palindrome vs. Rossini
(Published on 24. December 2014, 12:00 by Eisbär)
Richard 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.
Palindrome
Place the digits from 1 to 9 in every row, column and 3x3-block. The digits on the colored line form a palindromic sequence from one end to the other.
Rossini
The arrows outside the grid indicate that the first three digits are in ascending or descending order (the highest digit is at the sharp end of the arrow). If there is no arrow outside the first three digits cannot be in either ascending or descending order.
Richard and I wish all puzzle friends a Merry Christmas!
Solving hints
R9C3 = 9
9 in Block 9 in R8C89
9 in R7 in R7C56
9 in Block 2 in R1C4 or R3C5 (because of Palindrome 9 not in RC6)
9 not in R3C7 because of Palindrome
9 in C7 in R45C7: R7C6 = 9 ; R5C7 = 9
R3C7 has minimum of 5: R3C7 = R7C2 = {56}; R7C3 = {67}; R3C6 = {67}
8 in R7 must be in R7C5
8 in C7 must be in R9C7; R8C3 = 8
1 in R2C89 ; 1 in C7 in R4C7 ; R7C4 = 1
R3C7 must be 6; R3C6 = 7; R7C2 = 6 ; R7C3 = 7
R8C7 = 7
Solution code: Both main diagonals. First from top left to bottom right, then top right to bottom left.
Comments
on 4. October 2022, 18:48 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.
on 16. September 2016, 11:58 by CHalb
Great puzzle!
Great great puzzle!
...
One more big THANK YOU guys. That's a final [master]piece in this beautiful conceptual cycle.
on 3. June 2015, 12:20 by Statistica
Hi marchino75. Look here (search-site): http://www.logic-masters.de/Raetselportal/Suche/erweitert.php?skname=x&suchtext=Double%20Dutch
on 3. June 2015, 10:52 by marchino75
Good morning. Is it possible to have the full collection of 24 double dutch sudokus advent?
on 6. January 2015, 20:19 by Toastbrot
@Richard: Unfortunately I can´t see the comment from 25-12-2014; 05:16, but pin7guin gave the me the crucial clue.
@pin7guin: Als ich die Worte "fehlende Pfeile" gelesen habe gab es hier im Haus ein markerschütterndes ARRRRGH. Anschließend habe ich auch zum ersten Mal den letzten Satz der Beschreibung von Rossini gelesen. Jetzt weiß ich warum ich an einer Stelle so dermaßen festgehangen habe und nur mit Probieren weitergekommen bin. Das ich mit der ersten Fallunterscheidung gleich einen Treffer gefunden hatte wundert mich jetzt auch nicht mehr, denn wer weiß wie viele Lösungen es ohne die von mir vernachlässigte Regel gibt.
Vielen dank Euch beiden für Eure Antworten.
on 6. January 2015, 11:30 by Eisbär
@ Realshaggy: Thank you for your super-comment! :-)))
on 6. January 2015, 10:42 by pin7guin
@Toastbrot: Überprüfe nochmal alle vorhandenen und fehlenden Pfeile.
on 6. January 2015, 10:39 by Richard
@Toastbrot: you did exactly the same thing as RALehrer. See the comment from 25-12-2014; 05:16
on 6. January 2015, 01:00 by Realshaggy
Thank you very much for the calendar. As usual, I didn't had enough patience to do one puzle per day, instead I did them all last weekend (on three evenings). At least I couldn't get sick like from chocolate :-)
What I found very impressive (and I think this is mostly a compliment for Arvid) is that I have only printed the diagrams, and after solving, I can't tell you, which puzzles are from Richard and which ones from Arvid.
on 30. December 2014, 15:14 by uko50
Das waren ja eine Fülle neuer grandioser Ideen. Vielen Dank an die Rätselautoren und einen guten Rutsch ins neue Jahr.
on 29. December 2014, 23:40 by pin7guin
Lieber Richard, lieber Arvid, vielen Dank für euren leckeren, lehrreichen und anregenden Adventskalender! Ihr habt auch mir damit eine große Freude bereitet.
Jetzt bin ich komplett durch und wünsche allen, dass sie Frohe Weihnachten feiern konnten und einen guten Start ins neue Jahr.
on 25. December 2014, 21:40 by Danielle
Thanks for a wonderful advent calendar with a very nice final! Merry Christmas everybody! Fröhliche Weihnachten allerseits!
on 25. December 2014, 10:12 by flaemmchen
Vielen Dank Euch Beiden für diesen wunderschönen Adventskalender und Frohe Weihnachten!
on 25. December 2014, 10:00 by AnnaTh
Happy Christmas! I think the last one was my favourite!
on 25. December 2014, 00:29 by sf2l
Finished! Thank you both Arvid and Richard for this beautiful series. Glad I completed (just) before midnight (UK time...). And of course, happy Christmas to you both !!
on 24. December 2014, 19:57 by marcmees
Richard, Eisbar,
Thanks for this wonderful series with lots of new angles to look at sudoku.
on 24. December 2014, 18:39 by ch1983
Vielen Dank für die tollen Rätsel - ich wünsche allen ein besinnliches Weihnachtsfest.
on 24. December 2014, 16:54 by Statistica
Great series of wonderful Sudokus. THanks a lot and a peaceful Christmas!
on 24. December 2014, 14:23 by Fred76
Thanks to Richard and Arvid for this great series of sudokus.
I enjoyed all puzzles, the quality was constantly very high, and the ideas and designs were very nice.
Tomorrow will perhaps be a boring day without an advent sudoku to solve...
Merry Christmas to all LMD user !
on 24. December 2014, 14:11 by Mody
Merry christmas to you both. I have enjoyed every sudoku and I'm glad, that I have some unsolved sudokus of you for the next days :)
on 24. December 2014, 14:06 by Richard
Thank you for your kind words Arvid. I also enjoyed the whole process, from late spring till now.
What I liked most is to see your interesting and inspiring ideas and how you have improved your Sudoku-writing-skills since our previous Calendar! The pleasure was all mine. :-) Thanks for the fun time we had.
on 24. December 2014, 13:43 by Eisbär
Merry Christmas to you too Zoran! :-D
on 24. December 2014, 13:40 by zorant
Thank you to both of you for all great puzzles. Merry Christmas!
on 24. December 2014, 13:15 by Eisbär
Merry Christmas to you too Gabi! And of course again a big thank you for all the translations, tests and comments :-))))
on 24. December 2014, 13:13 by ibag
Hi Richard and Arvid, thank you for that wonderful calendar. Merry Christmas!
on 24. December 2014, 12:16 by Eisbär
Dear friends,
Unfortunately all good things come to an end :-D
It was a pleasure and honour to create this calendar for you all! I hope you enjoyed it...
I also want to thank my good friend (and sudoku-guru :-D ) Richard for making this calendar happen. Since the idea came up last summer I enjoyed every minute of building this event up together with you.
"A friend is one that knows you as you are, understands where you have been, accepts what you have become, and still, gently allows you to grow."
- William Shakespeare -
Thank you Richard for being my friend!
Arvid
