Rotational Sums of 9 or 18
(Published on 14. April 2026, 18:32 by RailMan)
Normal sudoku rules apply. Place the digits 1 - 9 once in every row, column and box.
Digits separated by a white dot are consecutive. Digits separated by a black dot are in a 1:2 ratio. Not all dots are given.
Rotational Sums of 9 or 18: All digits in the grid have a 180 degree rotational opposite. Every digit and its rotational opposite add to either 9 or 18.
Solve Online : Solution Check is enabled
Try some of my other puzzles using Rotational Symmetry here:
Non Consecutive Thermo Symmetry
Solution code: Row 9
Comments
on 20. April 2026, 04:50 by NotSoMagnifique
The implications of the 18-sums made me chuckle.
RailMan: Yeah, it is funny, but it lets you do some different things with the logic. I wanted a rule that would let me make a puzzle with only white kropki dots. You can try it here https://logic-masters.de/Raetselportal/Raetsel/zeigen.php?id=000SEB
on 16. April 2026, 14:23 by henryjclay
rotational symmetry makes my brain hurt at first. but very satisfying to work through, and now i want to try your other puzzles!
RailMan: Thank you. I hope you enjoy my other puzzles as well.
on 15. April 2026, 13:39 by Ragna
Fun puzzle. Interesting ruleset. Thank you. :-)
RailMan: Thanks!
on 15. April 2026, 02:41 by nightdream
I unfortunately spent 20 minutes staring at my screen because I didn't complete a white dot, so I thought I was missing something obvious.... Once I found my mistake, the puzzle was fun to complete!
RailMan: Happens to all of us :)
on 15. April 2026, 01:59 by Pairot
Nice variation of the symmetrical rule. My brain wanted to sum to 10, took some time to adjust lol.
RailMan: Yeah, it feels a bit strange, but it lets you do different things with the rotational symmetry and kropki interactions.
on 14. April 2026, 19:27 by wuc
To me a great 1.5-2* puzzle. Great setting thx.
RailMan: Thanks!
