I got some very supportive comments on my last puzzle, Latin Quarter, including one from Tacocat that suggested a similar concept on a smaller grid for usability in SudokuPad. So I gave it ago! Hope you enjoy. If you do, please check out Latin Quarter as well, though a device with a larger screen is recommended.
Typically, Line constraints only interact with digits on Sudoku Cells, but in this puzzle they also interact with digits in Quad Circles.
In this example, the cell highlighted in blue is connected via a red parity line to a quad circle containing the digit 1. Because 1 is odd, and quad circles count as values along parity lines in this puzzle, the highlighted cell must be even.
Solution code: Column #5 of the Sudoku grid (6 digits, top to bottom)
on 26. February 2026, 09:36 by Snookerfan
Extremely fun up to and including the solution code, thanks!
on 26. February 2026, 07:56 by Exigus
Had a great time colouring and solving, thanks!
on 26. February 2026, 06:10 by Justalilguy
Interesting sudoku and easy to make mistakes if you're not careful with notations like me. Thanks for setting!
on 26. February 2026, 06:10 by cygne
Clarified solution code description
on 25. February 2026, 18:01 by TeamSchmidt
The solution code should say 6 digits.