[ECO code B00]
Black leaves the "Épine Dorsale" for the semi-close Barnes Defence (rarely played though used successfully by T.W. Barnes against Morphy in 1858). Black hopes for lines like 2.Q-R5+ch so as to reply 2..P-KKt3, 3..P-K4 while White loses a tempo in defending his (or her) queen. B-Alt.
White Black 1. P-K4 P-KB3
Example ends: Undo or Jump or Clear