[ECO code B00]
Polish Variation
Black develops his King's Knight to KB3(f6) and renews an attack on White's KP, aiming to switch focus to the QP with moves such as ..P-QB4, ..Q-Kt3.
White Black 1. P-K4 P-QR3!? 2. P-Q4 P-QKt4 3. Kt-KB3 B-Kt2 4. B-Q3 P-K3 5. 0-0 Kt-KB3
Example ends: Undo or Jump or Clear