There are Sudoku variants with extra constraints: Killer Sudoku (cage sums), Diagonal Sudoku, and even 3D Sudoku.
There are Sudoku variants with extra constraints: Killer Sudoku (cage sums), Diagonal Sudoku, and even 3D Sudoku.
"It is not enough to be a good player; you must also play well." — Siegbert Tarrasch
"It is not enough to be a good player; you must also play well." — Siegbert Tarrasch