White advanced his QP to the centre freeing his QB,
contesting K5(e5) and threatening 4.P-K5
or 4.P-Q5. Black pushes his King's Pawn out
one square to K3(e6) to close the path
used by his QB.
B-Alt.
White Black
1. Kt-KB3 P-Q3
2. P-K4 B-Kt5
3. P-Q4 P-K3