Chess Board
[ECO code C82]
OPEN RUY LOPEZ - Mackenzie Var.
White's QB3(c3) Pawn takes B-for-Kt on Q4(d4).
Black's KBPawn push on to KB5(f4) blocks White's undeveloped QB, for 16.P-B3..Kt-Kt6 with equality.
    White  Black     8.	PxP    B-K3
 1. P-K4   P-K4	     9.	P-B3   B-QB4
 2. Kt-KB3 Kt-QB3   10.	QKt-Q2 0-0
 3. B-Kt5  P-QR3    11.	B-B2   P-B4
 4. B-R4   Kt-B3    12.	Kt-Kt3 B-R2
 5. 0-0    KtxP	    13.	QKt-Q4 KtxKt
 6. P-Q4   P-QKt4   14.	KtxKt  BxKt
 7. B-Kt3  P-Q4!    15.	PxB    P-B5
Example ends: Undo or Jump or Clear