Doppelgangers
(Published on 18. March 2021, 22:24 by Kafkapharnaum)
Inspired by a comment Simon made on Cracking the Cryptic, I created what I’m fairly certain is a new form of sudoku, which uses the digit 0 (zero). You'll find a 4x4 example grid below the puzzle (EDIT: As pointed out by user SudokuExplorer, Richard came up with a similar idea, but with the extra constraints here, the two puzzles still feel quite different!)
Rules
DOPPELGANGER
– Every row, column, and box contains the digit 0 always, as well as eight out of the nine digits from 1 to 9 (ie, it's missing one digit that is not 0)
– No two rows, no two columns, and no two boxes may be missing the same digit
– For each 0 in the grid, the digits missing in its row, its column, and its box must be three different digits
KILLER
– Within a cage, digits must not repeat, and must sum to the total indicated in the top left corner (and note that a zero always acts as itself – ie, the lowest possible value – regardless of what digits it's replacing in its box, row and column)
LITTLE KILLER
– Clues outside the grid give the sum of the digits found along the indicated diagonal (arrow clues), or along the indicated row or column
– Digits may repeat along the two diagonals if allowed by the other rules
CTC app (tracking cells version)
CTC app (main grid only)
Here’s a 4x4 example of what a completed grid might look like (with extra info added outside for clarity):
Solution code: Column 3
Comments
on 11. February 2024, 13:19 by chrisj50
I enjoyed this very much - clean logical path, approachable, and no major sticking points. Probably a good intermediate puzzle for those who enjoyed the nanos but want something bigger!
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Thank you so much once again, glad you enjoyed that very first offering! :D
Seeing how you seem to be on a quest here, the next best stop I think could be the 'Nanodoppelgangers', a 4-pack of 4x4's all combined into one multigrid puzzle, which some have found rather tricky. But I think also at this point, you're more than equipped to tackle the 8x8 'Maverick' too. In any case, thanks so much again!
on 7. February 2024, 22:12 by The Book Wyrm
Nice puzzle! Having done many of your smaller puzzles before certainly helped with this, but it does feel a bit odd now solving one of these on a full-sized grid (lot more to keep track of here).
Very nice puzzle, makes good use of the constraints, and very impressive for your first puzzle with this ruleset.
on 21. August 2023, 11:39 by wullemuus
This one was so nice to solve after the more difficult ones- a forcing logic structure and that for very beautiful. Ideal to get familiar with zeros!
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Ah, thank you for solving this one as well, and for the kind words! -- I often feel like this one might be a bit outdated by this point, but you're right that it's probably still the best one to get a feel for the ruleset. Thanks so much!
on 28. May 2023, 15:24 by marcmees
nice. thanks
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Thank you for your solve on yet another of my Doppelganger puzzles -- I'm sorry that they're not more enjoyable for you :/
If you're still interested in the ruleset though, you might like DadJokes's 'Double Agent' better, in which he mixed it with double arrows :-)
not more enjoyable ???
on 20. March 2022, 12:41 by Piatato
Very nice! Now I guess I have to try the Lesser Doppelgangers before I try the beastly looking Greater one. :D
Edit: Oh, and 007.
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My, you're on a streak, thank you so much, I greatly appreciate it! :D
And by the way, feel free as a setter to use this constraint (as is or modified, like no '3 faces' restriction for example); that was my hope with that first puzzle. It still has a lot of unexplored potential, like 5's on German Whispers line for example! In any case, thanks again so much!
on 19. March 2021, 19:48 by SudokuExplorer
It was a lot of fun to solve, thanks for making it! :-)
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And thank you for coming back to solve it! :D
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Wow, I see you're featured on CTC! I didn't realize you were a master setter with so many creations, now I feel all the more honored for the attention you gave my puzzle! I haven't watched the video, so I'll be sure to give that puzzle a try when I have a second (or 10,000, hehe)
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Haha, I am no master setter! I have been setting for less than a year after finding CTC, though I did set olympiad maths puzzles before joining LMD. I would consider master setters to be those like users Richard, Realshaggy, ibag, zhergan, Luigi, Zzzyxas and others who have been perfecting their craft for many years. Good luck with the puzzle :-)
on 19. March 2021, 10:55 by PixelPlucker
This was fun! Very interesting idea too.
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Thank you for solving it!
on 19. March 2021, 05:15 by xiaofeixia
This puzzle is very creative and makes me very happy
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Thank you so much!
on 19. March 2021, 01:54 by SudokuExplorer
@Kafkapharnaum: You might be interested in Richard's Blackout Sudoku (id=0002NO) from his Sudoku Variant Series.
The blacked out cells behave a bit like the zero in your puzzle.
Your puzzle seems interesting :-)
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I went and solved it and you're right, it's quite similar! Only the constraints are different. It's crazy to think he came up with it while churning out variants at a weekly pace, when that one idea of mine took me all I got!
on 19. March 2021, 01:47 by BMEP
Oh wow! What a fun puzzle! I have to say that it was quite tricky... but incredibly clever... Keep it up man! That was the product of a genius! Just to know... which video did inspire you to do this?
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Thank you for the kind (very kind) words! I'm happy to hear it didn't yield too easily; maybe I felt it would cause I've solved it so many times while constructing it haha
About the video, unfortunately I don't remember. It was just good ol' Simon's trademark mistyping, but I was surprised zero could be entered at all, and when he commented about it on top of that, I knew there was a creative opportunity there!
