Dueling Dragons
(Published on 13. March 2025, 14:33 by IcyFruit)
Place a digit from 1-9 once each in every row, column, and cage.
If and only if adjacent digits do not sum to a prime number, shade the boundary between them. Shaded boundaries must divide the grid into exactly 2 regions. There may be shaded boundaries that lie within a region without fully dividing it.
A digit in a cell with one or more arrows indicates the total number of shaded boundaries in the directions of all arrows combined.
Solution code: Column 8
Comments
on 20. May 2025, 23:47 by Jackler
It took me like 90 minutes to even understand the logic here. Then another 65 minutes to actually solve this. Perfect puzzle. Fight all the way through.
on 24. April 2025, 14:52 by Fool on Hill
Brilliant puzzle - seriously difficult even when I got the idea of it. Enjoyed it, but it was one of my longer solves, and I had to wait a while until the right thought came.
on 20. March 2025, 11:56 by cyddrdrd
Really juiceful!
on 16. March 2025, 11:08 by askaksaksask
This was truly inspired, but beware the difficulty! This took me a few sit-downs to really get my hooks in. That said, there's some brilliant setting here, with some really novel ideas at play. After I parsed the fuzziness of the rules, theres some pressure coming from some really unexpected places that leads to some very rewarding aha moments. Kind of miraculous the latter half of the puzzle even solves, given the clue distribution. Really wonderful puzzle icyfruit. Thank you!
on 15. March 2025, 05:56 by smckinley
Brilliant idea and a great puzzle!
on 13. March 2025, 16:51 by bansalsaab
Hi @icyfruit can you please explain this part of the rule "There may be shaded boundaries that lie within a region without fully dividing it"
I am not able to understand how a boundary can be within a region.
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It's a cell boundary rather than a region boundary. All region boundaries are shaded cell boundaries (or the edge of the grid), but not all shaded cell boundaries need to be region boundaries.
