Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...f5/4. Nc3/4...fxe4/5. Nxe4/5...d5/6. Nxe5/6...dxe4/7. Nxc6/7...Qd5/8. c4/8...Qd6/9. Nxa7/9...Bd7/10. Bxd7/10...Qxd7/11. Qh5/11...g6/12. Qe5/12...Kf7/13. Nb5

Black's c7 and e4 pawns are threatened. 13...c6 saves one and, by kicking the knight, gains the necessary tempo to save the other.

Black still isn't worried about 14.Qxh8 which can be met by 14...Nf6 15.b3 Re8 16.Bb2 Bg7 or the quiet 16...Be7 ( 16...Bc5 is a well-known blunder because of 16.Qxf6+ Kg8 17.Qh8+ Kf7 18.Qg7+ Ke6 19.Qf6#) winning the queen for two rooks.