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. Nxc6/9...Bxh2/10. Kh1/10...Qh4

=Ruy Lopez:Riga Variation=

Black now threatens the weak f2 square with both knight and queen, threatening checkmate.

If white does not deal with the threat sufficiently, or plays an ineffectual move, black may be able to win with the following lines:


 * 11...Be5+ 12.Kg1 Qh2+ 13.Kf1 Qh1+ 14.Ke2 Bg4+ 15.Ke3 Qh6+ 16.Kd3 Nxf2#
 * 11...Be5+ 12.Kg1 Qh2+ 13.Kf1 Qh1+ 14.Ke2 Bg4+ 15.Kd3 Nxf2+ 16.Ke3 Nxd1+
 * 11...Be5+ 12.Kg1 Qh2+ 13.Kf1 Qh1+ 14.Ke2 Bg4+ 15.Kd3 Nxf2+ 16.Kd2 Qh6+ 17.Re3 Nxd1

Moves that would inhibit this are 11.Rxe4, removing black's control over the f2 square, 11.Bg5, threatening black's queen, and any move of the c6 knight, delivering discovered check.

It turns out, however, that only 11.Rxe4 can keep white ahead. 11.Bg5 Qxg5 12.Qxd5 Qxd5 13.Nb4+ leaves black up substantially, though it will win back the queen. Knight moves allow 11...Kf8, unpinning black's knight and more or less forcing a following 12.Rxe4.