Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...a6/4. Ba4/4...Nf6/5. O-O/5...Nxe4/6. d4/6...exd4/7. Re1/7...d5/8. Nxd4/8...Bd6/9. f3

Ruy Lopez:Riga Variation
a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h
Position in Forsyth-Edwards Notation (FEN) r1bqk2r/1pp2ppp/p1nb4/3p4/B2Nn3/5P2/PPP3PP/RNBQR1K1 b
Moves: 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Nxe4 6. d4 exd4 7. Re1 d5 8. Nxd4 Bd6 9. f3

Ruy Lopez:Riga Variation

White immediately (mistakenly) pulls the trigger on f3, allowing Black to escape with a draw starting with 9...Qh4! threatening to smash Whites kingside pawn cover and invade with both bishops. 10. g3 does not defend as Black uncorks 10...Bxg3! with at least perpetual check, exploiting the weakening of g3 caused by the f3 advance.

White must instead eliminate the attacker of f2 with fxe4. After the obvious 10...Qxh2+, the king cannot escape to f2 because ...Bg3+ wins the exchange - Black can then castle and enjoy a safer king and two pawns plus a rook for the two pieces. So 11. Kf1 Qh1+, and the king cannot run to e2 because of 12...Qxg2+ (13. Kd3 Qg3+ 14. Re3 dxe4+ and again it is Black with all the chances after the smoke has cleared). Whites last chance to escape is via 12. Kf2, but on 12...Qh4+ the king must retire to the back rank, as there is nothing savoury about either 13. Ke2 Bg4+ 14. Nf3 dxe4 or 13. Ke3 Qg3+ 14. Nf3 dxe4. Perpetual check!