Easy Peasy Sudoku Advent (03) - Killer Kropki
(Published on 3. December 2025, 06:00 by Richard)
This sudoku advent calendar contains 24 variants that were included in my Sudoku Variants Series (SVS) but turned out to be too hard to be solved by a wide range of puzzlers. I aim for difficulties of 1-2 stars and have written some general and/or specific hints as well. I hope some players will try the original SVS puzzle #323 after solving the advent version.
Killer Kropki
Specific hint for this puzzle:
The black dots in box 5 force a chain of doubling sums. There is only one possibility for that: 2, 4, 8, 16.
Apply classic sudoku rules.
A white dot between two dotted outlined regions indicates that the sums within those regions have a difference of one. A black dot between two such regions indicates that one of the sums is twice the other sum. When there is no dot between two regions, they cannot have sums that differ by one or are double. Digits may not be repeated in regions.
Use the fact that all cage-relations are given!
Solution code: Row 8
Comments
on 20. December 2025, 20:43 by JoBerlin
@Tws the message "Yea congrats! Looks good" is just Sudokupad saying "I don't know the solution to this one, but what you've entered fulfilled Sudoku rules".
To know which solution is correct here you need to use the the negative constraint
on 9. December 2025, 05:14 by Richard
Fixed minor grammar mistake and added the SVS-number to the link.
on 4. December 2025, 00:42 by iffy
Didn’t notice the negative constraint until the very end. I wonder if it would have been an easier solve if I’d used it. Still a fun puzzle tho!
on 3. December 2025, 21:54 by walid_tun
fun really
on 3. December 2025, 20:01 by dzamie
The logic required is pretty easy to figure out - it's just a matter of execution, which is a bit tricky. The negative constraint is also a really cool addition!
on 3. December 2025, 18:52 by Richard
Repaired a missing dot in R1 in the image and both online solve links.
My apologies...
Thx Rollo for pointing out!
on 3. December 2025, 16:23 by flutchman
Fun indeed. I'm having a jolly good Advent time. Thanks Richard.
on 3. December 2025, 08:24 by Piatato
Fun!
