Logic Masters Deutschland e.V.

6x6 Doppelgänger Somedoku

(Published on 9. December 2025, 01:14 by laquartetfan)

This is the first puzzle I've ever set. I wanted to create a puzzle with a ruleset combining two sudoku variants I've enjoyed a lot, somedoku and doppelgängers.

Any feedback is appreciated!

After receiving some feedback, I've rewrittten the puzzle rules to improve clarity, changed cosmetic aspects of the puzzle, and added a solution check. But the puzzle and its logic remains unchanged.

Rules:

DOPPELGANGER SOMEDOKU:

The puzzle consists of a 7 by 7 grid missing the R7C7 cell.

For n between 1 and 6, row n contains exactly one zero and n distinct digits from 1-6, repeating digits as necessary.

For n between 1 and 6, column n contains exactly one zero and n distinct digits from 1-6, repeating digits as necessary.

Row 7 consists of a complete set of the digits 1-6. Column 7 consists of a complete set of the digits 1-6.

For each zero in the puzzle, the digit in row 7 of its column is different from the digit in column 7 of its row.

ARROWS: Digits along an arrow sum to the digit in that arrow's circle.

XV-SUMS: Cells separated by a V sum to 5. Cells separated by an X sum to 10. Not all Vs or Xs are necessarily given.

ODD-EVEN: A digit in a gray circle must be odd.

Play the puzzle on SudokuPad.

If the rules seem confusing, this example of what a completed 4x4 grid might look like may be helpful.

Solution code: Column 3 and the digit in the cell below the column (7 digits total)

Last changed on on 10. December 2025, 16:03

Solved by luoji, gdc, 72kchunshuai, Silverscree, soyorin, Thuna, flutchman, gfoot, marcmees, jseng, Dermerlin, Aronana, nyxie, henryng, bodemeister, redovermars
Full list

Comments

on 11. December 2025, 07:49 by bodemeister
Nice little puzzle! Fun to step out of my comfort zone and have digit(s) that are actually missing in rows/column. Thanks for the puzzle!

on 10. December 2025, 16:03 by laquartetfan
I edited the image of the 4x4 example puzzle in accordance with the cosmetic changes made to the main puzzle.

on 10. December 2025, 15:57 by laquartetfan
In response to feedback, I rewrote the puzzle rules to improve clarity, changed cosmetic aspects of the puzzle, and added a solution check. But the puzzle and its logic remains unchanged.

Last changed on 10. December 2025, 16:04

on 10. December 2025, 06:31 by Aronana
Very fun puzzle, with a unique ruleset! Kinda nitpicky but it would be nice if there was a completion checker or smthn on the sudoku pad link. I look forward to trying more of yours!

laquartetfan: Thanks so much! Your comment inspired me to figure out how to add solution check to my puzzles, so thanks for that too!

on 9. December 2025, 22:20 by marcmees
nice puzzle. Thanks

Last changed on 9. December 2025, 21:02

on 9. December 2025, 18:36 by gfoot
Interesting combination - it took me a while to understand the rules as what "replaces" means is a weird concept when combining with somedoku. I feel like there must be a clearer way to explain the rules but I'm not sure what it is!

laquartetfan: Thanks for the feedback! I'm working on a full size doppelganger somedoku puzzle, and when I post that I'll try explaining the rules differently.

Last changed on 9. December 2025, 21:00

on 9. December 2025, 15:57 by flutchman
Nice puzzle indeed.
Great debut.

I don't think it's easy though.
This was my first somedoku and also my first doppelgänger: takes a bit of effort to understand what's going on.

laquartetfan: Thanks so much! I wasn't sure what difficulty to rate it, and it definitely helps to be familiar with doppelganger and somedoku logic.

Last changed on 9. December 2025, 21:02

on 9. December 2025, 14:23 by Thuna
It's a nice puzzle. It's fun to work through once you're in the right mindset as to how you are supposed to approach it.

I think the description of 0 "replacing" digits is confusing, though, because of the lack of correlation between what digit is not in the column/row and what digit the 0 "replaces". Not that I was able to come up with a better way to explain it.

laquartetfan: Thank you! I'm working on a full size doppelganger somedoku puzzle, and when I post that I'll try explaining the rules differently.

on 9. December 2025, 02:00 by laquartetfan
I fixed the images and links from my initial upload of the puzzle.

Difficulty:2
Rating:94 %
Solved:16 times
Observed:0 times
ID:000QH1

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Solution code:

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