1.Ba4	e5+
In order to save the knight
2.Nxe5	Nf2
If 2... Nb2, then 3.Bb3 and 4.Kc3
3.Ke3	Nh3
If 3... Nh1, 4.Kf3
4.Bd7	Ng5
5.Kf4	Nh7
The knight reaches safety, only to blockade its king
6.Ng6+	Kg8
7.Be6#
Birnov (1952)