X-Factor

Also known as:

Diagonal-Sudoku, Kosegenli, Sudoku Diagonal, Sudoku X, Sudoku X-tra

A standard sudoku, except that the numbers 1 to 9 also appear on the main diagonals. The additional rule ought to make the puzzle easier for solvers, but often this is not the case. As with many of the good sudoku variants, the additional assistance that the rule provides is cancelled out by fewer starter digits.

Related puzzles:

Futoshiki, Sudoku
The illustration of the puzzle Download example puzzle

Instructions:

Place a digit from 1 to 9 in each empty cell so that each row, each column, each 3x3 square, and each main diagonal contains all the digits from 1 to 9.

Appears in:

Beyond Sudoku, Chat Puzzles Select, Extreme Sudoku, Saga Magazine Puzzles, Sudoku Collection, Sudoku Puzzles