The New Sudoku Players' Forum

[Xuba]

How about having a different color for invalid numbers such that, in the same puzzle, you could pencilmark both valid and invalid numbers.

[Sudoku Master2]

How about having a different color for invalid numbers such that, in the same puzzle, you could pencilmark both valid and invalid numbers.

I like that idea. My friend actually has this electronic Sudoku game and if you put in the wrong number it blinks. And I liked that part of the electronic Sudoku.