| 1.Qf4!! | |
| Threat 2.Rh5 and Black has no adequate defence - [A] |
| 1... | d5 |
| 2.Qe5 | Nf6 |
| 3.Rxf6 | Bxf6 |
| 4.Qxf6! | |
| or [B] |
| 1... | Nd2+ |
| 2.Rxd2 | cxd2 |
| 3.c3!! | Qxb3 |
| 4.Bxg7+ | Kxg7 |
| 5.Qg4+ | Kh8 |
| 6.Qd4+ | |
| and mates, or [C] |
| 1... | cxb2 |
| 2.Rh5! | Nc3+ |
| If 2... Bf6 3.Qf5 h6 4.Rxh6+! gxh6 5.Qg6!! forces mate |
| 3.Kxb2 | Nxd1+ |
| Or 3... Rxf7 4.Qxf7 Nxd1+ 5.Kb1!! Qxd4 6.Rxh7+!! Kxh7 7.Qh5# |
| 4.Kc1 | Rxf7 |
| 5.Bxf7 | |
| (Not 5.Qxf7?? Bg5+) Black now has no satisfactory answer to
the threat of 6.Rxh7+ Kxh7 7.Qf5+ and mates - if 5... Bd7 6.Bxg7+ wins Black's queen |
| Fischer-Geller (1967) In the game, Fischer played 1.a3 and lost |