HSSC Appetizer (1) - Sudoku Mathrax
(Published on 16. December 2025, 06:00 by Richard)
The Dutch puzzle association WCPN is proud and excited to announce a fun online sudoku contest in the last week of 2025!
The contest consists of eight tougher sudoku variants. At the time that fits you best between 24 and 31 december you can start the contest and you then have 2,5 hours time to submit as many answers as possible. The puzzles are in pdf-format, like the grand prix and (qualifiers for) national championships.
The puzzle below was too hard for the contest, but suits very well as a tough appetizer. In the coming days I will publish a few more appetizers. Enjoy!
Sudoku - Mathrax
Solve online in Sudokupad. (If you want to participate in the contest, it is recommended to solve this puzzle on paper too. ;)
The contest is open to everybody who loves sudokus. The only thing you have to do is register yourself (at no cost) here. You can find the instruction booklet (IB) with all the info here.
Apply classic sudoku rules.
Some intersections of the grid lines are marked by a number and an operator (+, -, X, /) in a circle. The number is the result of the operation, applied to both pairs of diagonally opposite cells. An "E" in the circle indicates that all four adjacent digits are even; an "O" indicates that all four adjacent digits are odd.
Solution code: Column 1
Comments
yesterday, 13:52 by Qodec
Lucky us that this wasn't in the selection, or we wouldn't have been able to play this. Absolutely loved that!
on 20. December 2025, 14:58 by itsid
fun puzzle, looked easier as it was, but very fun solve.
Thank you
on 19. December 2025, 09:30 by SennyK
Another very fun and neatly set puzzle, thank you!
on 18. December 2025, 16:50 by wuc
Very elegant. Smooth and fun thx.
on 16. December 2025, 19:11 by Snookerfan
Fun and beautiful puzzle! I am a little surprised that this was too hard for the contest, because it was very approachable. Thanks
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Reply: well, maybe I used a bit of a confusing wording. We already had a few highpointers, and the Mathrax had to be one in the middle of the difficulty range. For that purpose this was too hard. :-)
on 16. December 2025, 15:05 by Franjo
Thank you very much for creating and sharing this lovely puzzle using the mathrax-constraint in an elegant and beautiful way - perfect!
on 16. December 2025, 10:21 by Piatato
Consider me appetized :)
on 16. December 2025, 09:47 by murder
wunderpuzzle!
