Chess Board
[ECO code C61]
RUY LOPEZ - Bird Defence
(The) Side Variation
White's KB3(f3) Knight wrongly removes the KP on K5(e5), inviting 4..KtxB to enable 5.Q-B3(f3). W-Alt.
Black develops his Queen to fork White's knight and KKtP (threatening White's rook), with a position of strong advantage similar to the Shilling Gambit.
	White	Black
 1.	P-K4	P-K4
 2.	Kt-KB3	Kt-QB3
 3.	B-Kt5	Kt-Q5
 4.	KtxP?	Q-Kt4!
Example ends: Undo or Jump or Clear