Black's KB pinned White's QKt (taking some
of the sting out of White's QP attack), and enabled
..0-0. White's King's Knight removes Black's KP
on K5(e5) and now threatens Black's QKt and
KBP.
White Black
1. P-K4 P-K4
2. Kt-KB3 Kt-QB3
3. Kt-B3 Kt-B3
4. P-Q4 B-Kt5
5. KtxP