This is an opening trap for White that all serious chess players know how to defend against. It begins with 1.e4 e5 2.Bc4 Bc5 (or 2...Nc6) Qh5 (see diagram). Black should have played 2...Nf6 which covers h5, and attacks White's e4-Pawn. White's threat is to take Black's f7-Pawn with mate, but Black can easily escape here with 3...Qf6. All of a sudden, White has to worry about his f-Pawn, and he is forced to retreat. If, however, Black had played 3...a6, then White could play mate with Qxf7#.