Day 12: Christmas Chaos!
(Published on 12. December 2025, 06:00 by SharpFox)
Half of the calender is already over! Time for another special.
Rules (quite a few):
- Normal 4×4 Sudoku rules apply in each of the nine 4×4 grids.
- The blue thermometer is a slow/frozen thermometer. Digits either increase or stay the same along the thermometer, starting from the bulb.
- Pink renban lines contain a set of consecutive digits in any order.
- On yellow nabner lines no two digits are the same or consecutive.
- The red line is a parity line. Every two adjacent cells on a parity line must contain one odd and one even digit.
- The blue line is a region sum line. 2×2 box borders divide the line in segments and each segment has the same sum. There may be more than one segment in a 2×2 box.
- The digits on an arrow sum to the digit in the attached circle.
- A white kropki dot connects consecutive digits. A black kropki dot connects digits, where one is double the other.
- A V connects two digits, which add up to 5.
- The empty cells between the Sudokus have no digits and no influence to any clue! (e.g. adjacent digits on a parity line must have the opposite parity even if there is one or more empty cells between them)
(PS. I admit it, my inspiration comes from the SudokuCon Quilt. A great puzzle!)
Solution code: The first digit of each Sudoku (row 1 and column 1) in normal reading order (9 digits):
Comments
on 21. December 2025, 16:28 by tstaffor
What a cool concept for a puzzle! It's definitely gotten me excited to try out the SudokuCon Quilt.
I ended up leaving box 3 for last cause it was a bit daunting.
on 15. December 2025, 08:11 by Kirra
Great fun!
on 15. December 2025, 03:43 by supersim2000
Thank you so much for this puzzle, SharpFox.
I really enjoyed how the individual 4x4 grids interacted with each other.
on 14. December 2025, 19:28 by SharpFox
Extend Renban Line to avoid using uniqueness
on 14. December 2025, 19:06 by Rollo
Es ist nicht eindeutig, und das ist kein Trick, sondern einfach falsch. Schade, ansonsten hatte ich viel Spaß.
on 13. December 2025, 02:26 by YoooDeej
this was a lot of fun! let us use a bunch of different rules with only a little interlocking. kinda like a box of chocolate, was a nice snack!
on 12. December 2025, 22:49 by darylkay
I like this type of puzzle, this just wasn't done well. There wasn't a unique solution, I couldn't break multiple puzzles.
on 12. December 2025, 19:17 by dzamie
This was pretty fun, and I was lucky to guess the correct digit for the renban in grid 9. I went back and tried again with the other digit it could've been, and it rendered grids 6 and 9 unsolvable.
Aside from that, though, it was fun to see the rules playing with each other.
on 12. December 2025, 19:15 by sfield
I agree with the user who suggested " extend the renban line in Sudoku 9 to R2C1" which is the easiest way to create a unique solution, and it is the solution intended.
on 12. December 2025, 14:53 by JVA
@Sharpfox the problem is that the rules do not specify uniqueness (as is the norm), so the deadly pattern is allowed
May I recommend you extend the renban line in Sudoku 9 to R2C1? That seems to clear the ambiguity
on 12. December 2025, 14:08 by JVA
Do boxes 6 and 9 have an unique solution? I can't find a way to disambiguate them
on 12. December 2025, 11:16 by Statistica
Denke auch, es ist nicht eindeutig.
on 12. December 2025, 10:39 by googuee
Nice puzzle! Thanks for sharing.
on 12. December 2025, 10:09 by Ste1729
The puzzle is very nice, but the solution is not unique.
It's unique for the first 7 sudokus I solved, but for the last 2, I think there is a total of 11 solutions.
