Here it is:
. . . | . . 4 | 5 . .
. 3 . | . 2 6 | . . 7
6 . 8 | . . 9 | . . .
-------+-------+------
4 . . | 2 . . | 6 . .
. 9 . | 6 . . | . 4 .
. 6 7 | . . 1 | . . 8
-------+-------+------
. . 6 | 3 1 . | 8 . 9
5 . . | . 6 8 | . 2 .
. . 1 | 7 . . | . . .
Can anyone give me a hint for the next move ?
As I'm stuck right now and just can't find it.