thinking in square rooms
(Published on 14. January 2026, 00:06 by aqjhs)
At the same time as the skyscraper one, ChinStrap came up with this concept for a doppelgänger puzzle, I hope you like the take on it.
- Doppelgänger Sudoku:
- In the 9x9 grid, every row, column, and box contains a 0 always, as well as eight out of the nine digits from 1 to 9 (ie, it's missing one digit)
- 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.
- Fill the cells outside the 9x9 grid with the digit missing from the corresponding row, column or box.
- Modified numbered rooms: Spaces around the grid contain the same digit as the digit placed in Nth position looking into the grid in the row/column, where N is the digit missing in the row/column.
- Digits in a big circle must appear in the surrounding four cells at least as many times as they appear in the circle.
Online in Sudokupad (and with extra note space).
See also:
- alte karte / ferneiland
- the cost of giving up
- the year of the dög
- huisgenoot gezocht (ft. ChinStrap)
- don't hurt yourself (ft. Calvinball)
- got too many pages stuck together + zuul with ThePedallingPianist
- split pearsonality / dopealgänger
Solution code: Digits on the column missing a 9, top to bottom.
Comments
on 24. January 2026, 01:17 by BloodbuzzCorio
Fantastic puzzle! I do find it very easy to make mistakes in the doppelganger ruleset (hopefully will do less of that as I solve more) and so had to restart a couple of times but that is purely a reflection on the solver and not the setter! Thanks aqjhs.
on 18. January 2026, 12:21 by wullemuus
Totally agree with earthpuzzles- I restarted three times though all was correct because of the first hurdle :(.
All your new DG variants are so surprising!
on 18. January 2026, 06:28 by earthpuzzles
Really enjoyed the logic in this! Flowed quickly once I got past the first hurdles
on 16. January 2026, 20:39 by War
Excellent ruleset, love the doppelganger in general, really loved the modified numbered rooms paired with the quadruples clue, made for a very fun puzzle. Opposing 0 logic is very interesting
on 15. January 2026, 22:41 by SirWoezel
Yes, agree with 5 stars! Fantastic puzzle.
on 15. January 2026, 03:34 by h5663454
...Paper tiger.
