[ECO code C29]
Bardeleben Var. - The Heyde Variation
White advances his Queen's Pawn to Q4(d4) supporting his KP, and frees his QB for development.
White Black White Black 1. P-K4 P-K4 6. P-Q4 2. Kt-QB3 Kt-KB3 3. P-B4 P-Q4 4. BPxP KtxP 5. Q-B3 P-KB4
Example ends: Undo or Jump or Clear