Typically, a sudoku grid is 9 x 9, containing 9 squares each with 9
inner squares. The rules of Sudoku are
that a number must not appear more than once in any row, column or within the same square containing 9 inner
With 2Sudoku there are two playing grids as the inner squares are divided into two parts - one path (shaded)
being for one game, and one path (un-shaded) being for another game.
When playing 2Sudoku the same number must not appear in the same divided inner square.
The same rules apply where the numbers are replaced by icons or by colours.