Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. d4/4...exd4/5. O-O/5...Nxe4/6. Nc3/6...dxc3/7. Bxf7/7...Kxf7/8. Qd5/8...Kf6/9. Re1/9...Ne7/10. Qxe4/10...Kf7/11. Bg5/11...d5

= Nakhmanson Gambit, Kf6 Defence, Rook Attack =

11...d5
Black is threatening to unpin the knight with ...Qd7 or ...Qd6. White's hopes of capturing the knight rest on immediately driving off one of its three  defenders, while keeping three attackers on it (so, not blocking the rook  with Ne5+). The only move that accomplishes this is 12. Qf4+, intending Qh4.