[ECO code D22]
Haberditz Variation
White advances his QRPawn to QR4(a4) to attack the QKtP, to continue 5..PxP, 6.QxP+ch (with advantage) or 5..B-Kt2, 6.Kt-B3..P-Kt5!? (less clear).
White Black 1. P-Q4 P-Q4 2. P-QB4 PxP 3. Kt-KB3 P-QR3 4. P-K3 P-QKt4 5. P-QR4
Example ends: Undo or Jump or Clear