X Marks the SpotG 5

X Marks the Spot G5:
Fill the board, leaving empty squares in an "X" shape in the center 3x3 block

This achievement requires that you fill in an entire board with numbers, except that five squares that form an "X" in the central 3x3 grid. This must be done in a standard Sudoku game initiated from the Main Menu and can be done on any difficulty. However, Hard or Expert is recommended so there is adequate empty space. When the board loads, you need to confirm that the "X" shape is clear in the middle grid. If it isn't, reload. You can proceed to fill the entire board, except the "X", with random, incorrect numbers. Once all other numbers are filled in but the "X", the achievement will unlock.