Bonus: Double Doku by Thomas Snyder
or solve online (using our beta test of Penpa-Edit tools)
Theme: Diagonals
Author/Opus: This is the 226th puzzle from Thomas Snyder, aka Dr. Sudoku.
Rules: Standard Sudoku rules. Additionally, there are two overlapping classic sudoku grids, and both must have valid solutions.
Note: No answer strings or timing here (honor system for when you solve it). I’m simply posting some “examples” I wrote as the Sudoku Grand Prix coordinator. Apparently some common variants aren’t common enough….
Solution: PDF
Excellent and enjoyable!