2 1 _   8 _ _   4 7 5
8 7 _   5 4 1   2 _ 9
4 9 5   7 2 _   1 _ 8
9 6 4   3 1 5   8 2 7
3 5 2   6 7 8   9 4 1
7 8 1   4 9 2   3 5 6
6 2 9   1 3 7   5 8 4
5 3 7   9 8 4   6 1 2
1 4 8   2 _ _   7 9 3
There is only one way to fill in the squares that I've filled in.   (unless I've made a logical error... in which case there is a small possibility that there are more.)  However,   there are three different ways you can complete this puzzle.